Stray Currents Are Still Destroying Your Pool... and Spa... Especially Your Heater

Got this great comment today from PFLOVING in response to one of my first posts, in October '06, Why Salt Sucks. I didn't want it to just be buried in the comments so I'm creating a post just for it:

Found this blog and boy u guys are onto something. I too am battling this question on corrosion. here is my story. I have a hot tub with a swg eco spa generator. Made it one year and the inline heater started to show signs of corrosion around the heater terminal. It was replaced and my pool guy placed a zinc anode disc in the strainer basket and ran a copper wire to the bonding/ground terminal on the side of the balboa heater box. In 3 months the heater was toast. The stainless turned into a rusty dripy mess. The thought was that the swg was putting out too much clorine and maybe aggressive water since he had installed lots of these swg's without very many problems in our area. I questioned the bonding that was done from Coleman since it wasn't a contiuous wire linking all the pumps and heater together. So that heater was replaced and all the bonding was tightened down the way Coleman had installed it since most connections were very loose and dielectric grease placed on those connections. 2 months later now the new heater is destroyed....eaten up. He doesn't know what to think but I know it is stray current in salt water and dissimiar metals causing this. I also think, from my research, that the titanium plates and the stainless in the heater are reacting. The zinc anode goes uneffected since its not bonded to anything, at least thats my thought. One person in the industry suggested to bond everything together but don't hook that bond up to ground or back to the house panel as this is where you get stray current. This way everything is at the same potential. Also hook the zinc anode to the bond wire which it will complete that circuit and the zinc should dissolve and not the stainless heater. Thoughts?

PF: thanks for the great comment!

And, yes. I have quite a few thoughts on this subject. Your description of the problem fits in exactly with what I've come to believe about salt pools; if there is any Stray Current on the grid, proper bonding and salty water will amplify it's damage. Not to say that every electrical appliance attached to a pool shouldn't be properly bonded. They absolutely should be. That's how we keep people safe in water that is filtered, circulated, sanitized and illuminated via electrical devices; through proper bonding.

That's why I can't say that your idea of creating a separate bonding grid for your spa is a good one; because I don't think it would meet code. Check with an electrician in your area to be sure. But the last thing you want to do is to compromise your bonding where water and people are involved. And you may say that you're just creating a separate grid from the other, so it will be safe and isolated from the problems. But if anyone gets hurt, all that will matter is that you may have violated code to try to create a less susceptible bonding grid.

Second, Ground is Ground the World 'Round. Driving a new rod into the ground a few yards away from where your house's bonding rod is doesn't change much. If there are Stray Currents in the vicinity, they will be felt on your new grid as well.

Any electricians out there who want to contribute here, I'd appreciate it. I think my logic is right on this, but I invite everyone's input.

Having said all that; the fact that your second heater failed faster than your first heater AFTER you cleaned up the bonding indicates that the better the bonding for the appliance, the more susceptible it will be to Stray Current Corrosion. IF there is any Stray Current on the grid, it will be amplified by the highly conductive salt water and the cleaned up bonding grid will present even less resistance and a more conductive path to the equipment, in this case your heater.

So, the issue becomes one of either getting rid of the amplifier (salty water) or troubleshooting the grid to isolate and eliminate the sources of the Stray Currents. Here's a link to a story from a pool builder, Rod Ogilve, who had a similar problem with Stray Currents. It's a thread over at the APSP website about salt pools and what the builders think of them. Scroll down to his post that starts, "at the risk of sounding like another salt blast..." It is very applicable to your problem. After that, scroll through the whole thread while you're there. There's lots of great Horror Show pictures of salt damage to pools.

Also, take a look at this post; The Trouble With Heater. Scroll down until you get to the part in italics. it's the latest update to the Never Ending Saga of trying to find a pool heater that plays well with salt. So far, none do.

My best advice is take the salt system off your spa, use a little Twenty Mule Team Borax to soften the water and forget all your problems with Stray Current Corrosion. Or spend hundreds of dollars on electricians to find out that your neighbor two blocks away has a bad sump pump.

Good luck with your spa!

Making Salt Work

Did I say that? No, it can't be. Can it? 

Has the Pool Guy flipped his lid? Has he gone over to the Dark Side? The truth is, neither. But, contrary to industry opinion, I am a realist. And after all these years of fighting the Good Fight, I think it's time to admit that Salt Is Here To Stay.

I didn't say that was a Good Thing. I said it was A Reality. A Sad Reality. But A Reality nonetheless.

So, after a long hiatus, I'm back with suggestions on how to make your salt system work for you. I still think you ought to remove it from your pool. But if you're sold on your salt system and you just Gotta Have It, then stay tuned to The Pool Biz for articles on how to make it's integration work for you.

In that vein, some time ago, I wrote to the folks at the one of the Diving Board manufacturers - Interfab - and asked them if, in light of all that's gone down with salt over these last several years, they had developed any products that would be more salt compatible. Diving Board folks in general took about the biggest hit on any of the manufacturers that were affected by the salt craze. Imagine being them; three or four years of covering warranty in an environment you never foresaw - the 3500 ppm salt environment - and just when you're getting your feet back under you from that, with a new line of products designed to weather the salt storm, you wake up to the worst economy since 1932. Some days it doesn't pay to get out of bed.

But, when I asked them, toward the end of last summer, which were definitely rosier times, this is what they said:

"We DO in fact have products that are more salt friendly than others and would certainly mitigate rust in a salt pool environment. Products that we would promote for use in a salt pool environment include the following products:

Edge Diving System (NEW)
T7 Diving System
X-Stream Slide
G-Force Slide
Sacrificial Zinc Anode (NEW)
Powder Coated Rail Goods

As always, we’d have to stress to customers that there is no guarantee against rust or corrosion in a salt pool environment. By taking steps to ensure proper pool water/salt chemistry, that any return jets are pointed away from any in-pool rail goods, and that any necessary product maintenance is performed, you can certainly help diminish the risk of rust.

The diving set up that you saw in our counter brochure is called the Edge Diving System™. [Ed. note: I had written and asked about that system in particular. You should take a look at it. It's a unique approach to keeping the salt from corroding the diving board base]  It was specifically designed to replace all of the rusting steel Techni-Spring diving bases, and our competitor’s product equal, that are out in the field. The Edge Diving System is comprised of composite materials and fits the same 12” on center jig as the steel Techni-Spring base. I have attached both a photo of a rusty steel Techni-Spring base and an Edge Diving System for reference."

Now, take a look at the second photo, of the Techni-Spring base. It beats the salt by not attaching the base fasteners where the salt water can pool and lay and work it's corrosive magic on the threads. I mean, let's face it, if your jig is buried in the cement of your deck, with the fastening studs projecting up out of that, and the threads of those fastening studs are down at deck level where they can be compromised by the corrosion wrought by salty water, then you're looking at breaking up that deck to replace that jig. So, if you attach the base to those fastening studs about 10 or 12 inches above deck level, then you've put those threads somewhere that it's impossible for the salty water to pool around. It's hard to see where those bolts attach in that photo, you can click on it to enlarge it. Then, look where the spring is attached to the composite base. You'll see the rubber nut caps. That's where it fastens.

Here's a link to the T7 install PDF. Page 9 shows a very good photo of a cutaway of the base and the fasteners. See how they've moved all the attaching hardware off of deck level? Brilliant in it's simplicity.

They go on to say: "The T7 Diving System, X-Stream Slide and G-Force Slide are all upgraded products that are comprised of composite materials and very suitable for salt pools.... This year [2008], we started offering a sacrificial zinc anode, which we designed specifically to fit most residential pool ladders and rails. (1.90” OD) We recommend the use of the anode on any pool rail that comes in contact with the pool water. (Deck to stair rails, pool ladders, etc.) The anode is installed below the waterline and is in direct contact with the metal that it will protect. Generally, only one anode is required, however, if a pool ladder has plastic treads, you will need an anode for each 'arm' of the ladder since the plastic tread will not maintain the current flow. I have attached a PDF copy of the bag card that comes with the anode, along with a couple of photos of an actual anode."

They make a very important point there; if a pool ladder has plastic treads, you will need an anode for each arm of the ladder since the plastic tread will not maintain the current flow. What's interesting about this is how much we've all had to learn in order to deal with adding salt to pool water. These are engineering concerns that didn't need to be addressed before salt came along. Now they're part of ladder design, for example. Each action like this drives the cost of engineering, of the end product and, in the end, the final price tag for the whole pool. And we haven't even talked yet about maintenance, which will be in upcoming blog pieces.

Still think your salt system is cheaper than conventional chlorine? Read on:

"Lastly, powder coated rails offer yet another layer of protection against rust and corrosion for pool rails. The layer of powder coat paint acts as a barrier between the elements and the stainless steel rail. One thing to mention is that if a powder coated pool rail is winterized and continually pulled in and out of the anchor sockets, the risk of paint chips and scratches increases which expands the risk of rust at those damaged paint areas. For optimum rail protection, a powder coated rail in conjunction with a sacrificial zinc anode is the best way to go."

Powder coated rails. They're very effective, and they're beautiful, too. But they are not inexpensive, and you need to consider those costs as part of the price of maintaining your pool when a salt system is installed.

So, as you can see, I'm not selling out here. I'm not saying Salt's Great and I'm not shilling for a ladder manufacturer - although I think these folks have the best idea so far about how to keep that salty water away from their hardware.

Bottom line is I'm still against the idea of you putting salt in your pool. But if you do, do it right, and spend the money you need to spend so that a year from now you don't have a rusty mess on your hands.

How Salt Systems Don’t Work

There was a Pool Show in town here lately. It was a three day event. Lots of classes. Lots of exhibits. I’m sure a lot of good and sorely needed training got done there.

I didn’t go.

Not to say there’s anything wrong with Pool Shows. But, except for the rare class or two taught by people on the Tech Side of Life With No Monetary Interest In Whether You Buy What They’re Teaching (and you good guys and gals who do that know who you are and we love you for it) the rest of it is just A Show.

But, it’s the only time I ever find myself feeling sorry for Sales Reps. Think about it; standing at a booth all day long, trying to figure out ways to make a black plastic pool pump look and sound sexy. How hard is that?

The reason I bring The Show up at all is that they had one seminar, added to the schedule at the last minute, titled, How Salt Systems Work.

As I said, I didn’t go. I heard, though, through the Pool Guy Grapevine, that in some of the other seminars, those that were water chemistry centric, the main complaint of the folks in attendance was What The Hell To Do About These Damn Salt Systems. Of course, the people attending the water chemistry seminars were the “hands on” folks, the ones who see these systems in the field and try to explain to their customers each day why their pools are falling apart.

But enough about Pool Shows. Let’s talk about what happens when Salt Systems Don’t Work.

Here’s a picture of a salt cell plate that was about three years old when we replaced it.



This is the center plate in a pack of seven plates. This is The Weak Link In The Chain, so to speak. It gets eaten alive by being the return path for all of the current flow. As you can see, it is literally eaten alive. The way it works is that current is applied to one of the Outer Plates in the pack of seven adjacent plates by an insulated conductor. That plate is electrically connected to the outer plate on the other side of the pack by another insulated conductor. Then low voltage, high current is applied to these outer plates. The current jumps from the two outer plates to the next two plates, then in turn to the next two plates, and then, the plates on either side of the center plate deliver their full current flow to it, and it provides a path back to the power supply to complete the path for current flow.

Here’s a basic drawing of what’s going on, using a simpler, three plate pack as an example. Don’t laugh. I don’t use PC Paint very often.



The first plate in the foreground receives current flow from the battery – in our case, a power supply – and it passes that current flow over to the last plate in the background via that heavy dark line, which if you crack open a salt cell with a sledge hammer like I did, you’ll see is an insulated bar to avoid stray conduction to the center plate as the current flows through it. Then, the Magic of Electrolysis occurs. The current flow – up to 8 amps of current – passes from the two outer plates to the center plate through the water. That’s why you have to add some salt to your pool water. Without it, the water wouldn’t be conductive enough to pass the proper amount of current flow.

Part two of why you add the salt is so that, with that big whopping current flow, you zap the inactive chloride ion that got there when you poured the salt into the pool. When you pour it in, the salt immediately dissociated into sodium and chloride. The chloride is just in there, doing nothing, until it passes between those cell plates and the current flow turns it into Cl(little lower case 2), which is an oxidizer, and that Cl(little lower case 2) mixes with the water to form hypochlorous acid, the killing form of chlorine.

That’s where those Salt Reps get off telling you that you only have to add salt once. When hypochlorous acid does its job and kills something, the HOCl (hypochlorous acid) dissociates and that Cl is back to being an inert chloride ion again. Now, the next time it passes through the cell plates, it gets zapped back to life, mixes with some water and makes HOCl all over again.

So that’s true. Once added, you never have to add salt again. As long as your kids never splash even a drop of water out, as long as you never backwash your filter, as long as you don’t have any water features which aerate the chloride rich water, as long as it never rains and dilutes your pool water. Which is why, in spite of the way the Salt Reps twist the science to make it sound like There Really Is A Free Lunch And This Is It… there really isn’t. But you knew that, right? They are, after all, salesmen. What did you expect?

But getting back to why I took pictures of that cell plate. Oh, by the way, for comparison, here’s a picture of what’s left of that cell plate alongside one of the other plates from that pack that was lucky enough not to be in that center, return to battery, position.



When this salt cell failed the only indication we had was that the chlorine level in the pool kept getting lower and lower. Depending on the time of year, you could go more than a couple of weeks before you make the decision to spin the connectors off the cell and take a look inside.

During that time, from the moment that Return To Battery Connection just dissolved away and there was no longer a return path VIA THE SALT SYSTEM for current flow, where was that current flow going? The power supply still had +28 VDC available at it’s output, and the physical connection to the two outer plates was still there, but there was no longer any way for those plates to do their little Jump From Plate To Plate trick and return, finally, to ground.

You see, in a perfect world, current flow follows the path of least resistance. So, on Day One of operation, these salt systems are operating exactly as they did in the lab, when they proved that they were emitting less than the maximum allowed Stray Currents to receive their UL listing. But when the salt cell fails like this one failed, the current flow starts looking for new ways to get to ground, back to battery, as it were. And it will follow any path it can find to get to ground. The more resistance there is, the less current will flow. But when you’re starting with 8 amps, you can still have a pretty healthy current flow when it finds it’s way via other paths to ground.

Paths like: Salt cell plates to bonded (grounded) and very expensive heater. Or salt cell plates to bonded ladder or grabrail. Or salt cell plates to bonded light niche. Or salt cell plates to anything metal that is submerged in your pool. But still you should be safe, right? I mean, that Stray Current flow will go right to ground via the bonding lug, right?

Well, that’s when you get to add in Galvanic Corrosion to the Stray Current Corrosion. Take a pool ladder, for example. Stainless steel mounted into a brass anchor cup set in the deck. Now, splash salt water on it all day every day the pool is being used. The chloride rich water sets up a Galvanic Cell that causes corrosion to form BETWEEN the stainless rail and the brass anchor cup. That presents resistance to current flow. Now, you come along and grab that handrail and you get a tingle. Because you present less resistance to current flow than the corrosion building up in the anchor cup. And when you have that scenario, you go out and Google for:

Salt system conducting electricity on handrails

That showed up on my Site Meter this week. But that’s nothing new. I’ve had lots of hits like that over the last year and a half.


Now let’s take this a step further. Let’s back this scenario up to when the salt cell’s center plate first started to deteriorate. I’m guessing, but from the looks of it, I’d have to say that this plate was in pretty bad shape for over a year. So, for over a year, it wasn’t able to provide as efficient a path to ground as it did when it was brand new, and I’d say that the Stray Currents were ramping up from the minimally allowed level to something that sends people out on the internet Googling for things like:

Pool salt system conducting electricity

How do you troubleshoot a swimming pool heater plumbed with plastic pipe for electrical electrolysis

Stray electric current salt water pools

Zinc anode skimmer basket does it work

“Chlorine generator” “copper pipes”

Dealing with stray currents around pools (from Australia… Imagine that)

Using the old Site Meter info again, in a sample group of the most recent visits, this represents 17.5% of the people who come to my blog via a Google search.

Now let’s take this even a step further. This deterioration of the plate begins the minute you plug the salt system in the very first time. So, it’s a safe bet that the Stray Current Corrosion begins within a few days, weeks, months (?) of your system being brand spanking new.

Every manufacturer admits that your salt cell is only going to last you about 10,000 hours, which under normal use is from three to five years, and the reason why is because they know that from day one, the cell plates are wearing out just like this one did. And my contention is that as they wear out, the Stray Current Corrosion is ramping up.

From Day One.

These cell plates are made of ruthenium coated titanium, which, in the Galvanic Series, is just about the hardest, most noble, least active, least cathodic metal compound around. And still, it disintegrates with current flow. Your brass and copper and stainless steel pool components don’t stand a chance.

Another thing that makes me think I'm on the right track here is something I remembered reading in the Save-T 3 automatic pool cover owner's manual, on page 13:

"Since 1999 when Underwriters Laboratories (UL) dictated that all metal components of automatic pool covers must be bonded to the pool grid, we have seen an increase of galvanic corrosion [emphasis mine] on some of the aluminum components. In addition, the popularity of electric chlorinators where salt is added to the pool water has increased."

Here's the link. It's a slow loader, but it does work.

What that's saying to me is that, as the salt cells age, and as they emit stronger and stronger stray current, we see more and more corrosion in any metal that's bonded to the pool grid, as that stray current seeks a way back to ground. Like the pool covers; the incidence of corrosion INCREASED after they were required to be bonded to the pool grid.

Anyway, that’s why I wanted to write a blog piece about How Salt Systems Don’t Work, because I’m sure that none of this was brought up in that industry sponsored seminar, How Salt Systems Work.

So, the next time one of your customers asks you, "Didn’t you just replace that (fill in the blank with your favorite salt damaged component) a couple of months ago?", just print out this blog piece and hand it to them and say, “Yes, and here’s why we’re going to do it again real soon”.

Unless, of course, you sold them the salt system, too. Then you’ll just have to do what everybody else is doing; shrug your shoulders and pretend that you don’t know what’s going on.

Good luck with that.

Stray Currents Are Still Dissolving Your Salt Water Swimming Pool, Part Three


I have tossed around the term Stray Current a lot lately. Before, I always thought of it as just another name for Galvanic Corrosion, until I was contacted by a pool builder who specializes in in-ground vinyl lined pools. He explained how he had been chasing Stray Current Corrosion issues for the last fifteen years, since way back to the Lectranator days. Once I started reading up on Stray Current Corrosion, about three weeks ago, I found that it's prevalent in DC systems. Like our salt systems. When you add in the Galvanic Mismatch of the metals we use in our pools, it explains a lot.

I’ve printed his comments about the problems he’s seen in previous blog pieces. In fact, his quotes are what started me titling my weekly installments as “ Stray Currents Are Dissolving Your Salt Water Swimming Pool”.

You see, it wasn’t until I talked to him that things started really gelling in my head and I was able o say that I really understand the theory what’s happening to our pools with salt water chlorination. That’s what the manufactures are counting on; that it’ll be too hard for us to put all the disparate pieces together to overcome their lies.

Like when I first started asking questions about why everything was falling apart, they would say, “We’re only using 3,000 ppm salt. How could that be corrosive? Salt’s not corrosive until…” then fill in the blank with the myriad BS salt levels they come up with.

Then, when I asked, “What about galvanic corrosion?” they said, “It can’t be galvanic corrosion because the metals aren’t touching.” And that answer really stumped me for awhile. I couldn’t figure out how to get around that. I knew the pool metals were corroding, and I knew that it was really only happening so very rapidly on salt pools, but the truth is the metals weren’t touching. So what was causing it?

Then I got his first e-mails, where he talked about chasing Stray Currents and talked about how those Stray Currents were corroding the lugs off the pool bonding wires, and everything started making sense.

So, I asked him for a procedure that we could all use to see for ourselves what was going on with our salt water pools. The following is what he sent me:

Before I start with this, I want to make sure you understand that I fault no particular manufacturer, but rather this applies to all products identified as "Salt Chlorine Generators" that produce sodium hypochlorite through the cell process. That is mostly because you don't have to look hard to find out who makes the cell plates for everyone. It just happens to be the same guys who make titanium exchangers for most heat pumps.

I have thought some on the step-by-step process where a pool can be checked. I guess the best I can say is that it is very situational, i.e. what components are on a pool, what level a generator is running at, length of grounding run to equipment, style of coping, and so forth.

I tested two pools yesterday that are built very much the same so that I would have a basis of comparison. Luckily, one was mine and the other was our lead technician who, up until recently, sung the praises of salt as "just too easy". I welcomed the opportunity to publicly tell him "I told you so" when he mentioned that his aluminum coping was starting to erode. His question to me after I had him do some extensive measurements on his pool, was please explain why my pool is doing what it is doing. I must have had a smirk on my face during the entire explanation, but I was glad to at least have a solid convert under my roof.

What we got yesterday was as follows. First reading is from his salt pool, second reading is from my erosion feeder pool:

Amps 0a 0a
This was not the norm, but it has been very dry and the ground wire was shallow.

DCV 480mv 10mv
Measured from water to ground

DCV 750mv 50mv
Measured from water to aluminum coping

ACV 380mv 150mv
Measured from water to ground

ACV 250mv 30mv
Measured from water to aluminum coping

Res. 5 ohms 500 Kohms
Measured from water to ground

Ohms 10 ohms 400 Kohms
Measured from water to aluminum coping

The point of these measurements is to give an indication of the "conductivity" of the pool. Since these pools were built in the same way, using the same materials, and I am pretty sure by the same builder, I think there are some clear implications. First, the only difference between the pools is that his has a salt system and mine a simple erosion feeder. I take no better care of my pool than anyone else and I also think that they were built at the same time.

What I always focused on was the DC voltage in the water and the resistance to ground. The higher the voltage (I have measured up to 1 volt in some cases) and the lower the resistance (2-3 ohms being the lowest) the faster the problems presented. Now I know that a quick student of ohms law would tell me that the higher voltage is due to a larger resistance to develop a "load" and that it should not be possible to have both a higher voltage and lower resistance given similar circumstances. However, there are other factors that would allow such an occurrence and they are far too complicated for this explanation.

Since the origin of the voltage is the cell (no matter what the manufacturer says) which to an average student of battery operation would conclude that starting at the cell, the current must migrate back to the source to complete the path. I think the builders of the cell would argue that the current is passing straight from one cell plate to the next in a closed loop at the generating cell. I guess I would just say then that perhaps the water rushing by the plates must "wash" some of the electrons out into the pool unintentionally and they just fall harmlessly to the bottom of the pool waiting to be vacuumed later. Clearly, under the best of circumstances, current will find multiple paths back to the source (path of least resistance notwithstanding). I am not implying that all the current generated at the cell is passing through the water. What we are talking about here is "stray" current that is not intentional. Otherwise the speed of deterioration would be much more dramatic.

Our experiences are not limited to vinyl. The problems are across the spectrum of pool construction and include concrete and fiberglass. The only difference is what is does to the particular surface material. What is common is what happens to metal components: Ladders that rust into nothingness, stainless niches that lose their conduit connectors, ground lugs, and niche rings, aluminum coping that starts decaying at the point where it meets the concrete, and so on and so on. I have ladders laying in the yard that look like they were processed in an electroplating bath. Then there are the countless pools that shock the users because some or all of the ground connectors are decayed into non-connection. Why? Current migration back to the source. However you want to define the process whether galvanic corrosion, electrolysis, (insert your type here), the result is the same. And in cases where the water carries a contaminant such as magnesium, the gray staining is also present.

In these cases, the gray color was pronounced on locations that would be most likely to allow current migration. Specifically, the stains were at the panel seams, wall bases, floors where the water jet forced water, etc. We actually sent liners away to labs to have spectrum analysis run on them to identify the stains. While we understood the items found, it took a while to connect the cause.

In all of these cases the common factor was a salt system. Now, we could not blame the units where the customer just let them do their thing without checking them from time-to-time. In those cases, when the chlorine got to 50ppm plus, it was hard to blame anyone else for what happened to the liner. That is when we found out that a liner can "absorb" half its weight in water under the right circumstances.

But like I said earlier, at least an erosion feeder would run out after enough neglect. What got terribly old through all of this was the manufacturers oft repeated phrase, "well I just don't know what to say, none of my other dealers are having this problem" or "I swear, it is only happening to you guys". This was repeated enough that we warned our reps that if they said that one more time, they could not return to the property--ever.

It has been about three years or so now and I am happy to report that our problems have gone away completely. I think it is no coincidence that it was about the same time that we stopped installing salt systems of any type. At this point, there is no sales person alive that could make an eloquent enough speech to convince us that the units are "fixed" and we would do well to "try" them again. That issue is dead for us and we won't even talk about it with anyone.

So, there you have it. Of course, the same old squeaky wheels out there – the Salt Reps – are going to say, “that’s just one builder. His findings don’t represent the whole industry”. And while that’s true, stop and ask yourself why his findings are the only findings available when there are reports nationwide about the very things that he and I are talking about.

Let’s face reality for a minute. These salt manufacturers are making boatloads of money selling you on the Joy of Salt, and the other half the industry is making a buck saying that all salt pools need sacrificial anodes because of incidence of staining, discoloration and metal deterioration – like Pool Tool Co and others. This is a problem. The whole thing is degenerating into a snake oil scam. The Salt Manufacturers are taking all this profit, walking away from all this damage, leaving the builders and service companies and other manufacturers of products destroyed by salt stuck with the liability for all this damage.

And the reason that research like what our friend has given us is the only research we can find is because the manufacturers already know that any real peer reviewed research that is performed will only point to the fact that they're baling water on a sinking technology; salt water chlorination through electrolysis.

And the proof is in the "companion products" being sold with salt systems. Pool Tool Co,on their own website, says that sacrificial anodes will stop plaster discoloration, metal erosion, heater damage and black stains around your pool light.

http://www.pooltoolco.com/catalog4.html

These are smart people at Pool Tool Co. They know that the problem exists. How can the manufacturers keep stonewalling and saying, “Nah, you’re seeing things”? Somebody’s lying to us. So when you show this handy dandy little procedure for checking for Stray Currents to your Salt Rep and he says, “No way. Stray Currents don’t exist,” tell him that he needs to get an injunction against Pool Tool Co then. Because the Salt Reps have already told us, it can’t be Galvanic Corrosion.

You see, the metals don’t touch,and we're only using 3,000 ppm, and you must have bonding issues, and you're using inferior grade stainless steel, and, and...Oh, look. I've run out of excuses.

Stray Currents Are Still Dissolving Your Salt Swimming Pool




"It is difficult to get a man to understand something when his salary depends upon his not understanding it." – Upton Sinclair

I often get e-mails from Salt Reps. Often, they are not pleasant. I understand why. If I’m successful in getting the word out about how salt is destroying your pools, their world will have to change. They’ll have to get a new hustle. So I understand when the tone of their e-mails drifts over the line a bit.

Like Sean Assam at AutoPilot. He sent me a flurry of e-mails this week. You see, Sean’s convinced that an exploding salt cell I talked about some weeks ago blew up because of a water hammer in the in-floor cleaning system and not because of hydrogen gas buildup. And he’s been dogging me for more details about the incident. Not because he wants to help make Mr. Baker, the pool owner, whole again. It’s not Sean’s system that blew up. It’s because he wants to point out that the "Clearwater manual... cautions against operating over 29 psi (if I recall correctly). I'd say most in floor systems operate at 25 - 35 psi on a routine basis", then later, "AutoPilot does not have a clear body cell. We can handle and have been tested by NSF to 60 psi."

He did offer up one interesting side note on his way to pointing out this pressure sensitive Market Separator, "AGAIN, I'm not saying that it [hydrogen buildup and explosion] couldn't happen as I've seen the results of an exploded cartridge filter. The homeowner, who also happened to be the pool service contractor, admitted to installing the system incorrectly and causing the resulting damage. Basically he jumped out the flow switch rather than replacing it, lost prime and the rest was explosive."

I spent some time when I first got out of the Navy as a Logistics Engineer for a defense contractor. God-was-that-a-boring-job. It’s the main reason I ran away to the Pool Circus. But one of the things I studied as a logistics engineer were failure modes; all the different ways that a component, like a flow switch, can fail. Then we’d extrapolate what the results would be. I’ve done enough of that kind of forecasting to be able to say that there By God is at least one failure mode for that flow switch that will act the same as if it were bypassed (Sean’s jumped out). Something as simple as the contacts sticking together when the pump loses prime will make the system think that it’s supposed to keep operating.

So, there’s another Salt Rep on record admitting that salt chorine generators can explode.

You can read about the exploding chlorinator incident here:

http://thepoolbiz.blogspot.com/2007/02/boom-goes-salt-cell-this-weeks-blog.html

But the exploding chlorinator was really just cover for why he wrote to me this past week. I think perhaps he’d asked for one too many extra shots at the Starbucks drive thru, because once he’d built the pretense for the e-mail by asking again about the water hammer theory, he began ranting about last week’s Stray Currents blog piece:

"Why do you only give credibility to the dealer [sic] that have problems and blame salt... Why is there such merit given to a builder that blame [sic] salt for doing the damage to the bonding grids and causing electrolysis or causing the pool water to shock his customers because it has corroded the bonding grid???? What research was done to determine this? 15 years of researching the pools he's installed with salt systems? 200 pools/year x 15 years? WOW, that as much as 3000 salt systems! Why didn't this builder go out of business after 2 years of salt systems? What research did they do to evaluate the soil conditions? How much salt was in, or HOW ACIDIC was the soil to begin with? Where did they get all the salt from, the pool water from backwashing? [Pool Guy Note: Right here, Sean makes my case for me. I have been saying over and over again in this blog that backwashing your salt pool is going to have an adverse effect on your soil. If you can sorta read between the lines of his rant, you can see that what he’s saying is that backwashing your filter onto the ground around your pool is just as likely to create corrosive soil that did the damage to the bonding grid as Stray Currents. You have to wonder if it’s not because he’s seen that situation. But whether it’s Stray Currents or salty soil that caused the damage, getting rid of the salt system will fix the problem. The fact that Sean can’t see that goes back to Sinclair’s quote at the top of this blog piece. Now, back to Sean;] Where is the logic to your last blog's dealers letter blaming salt systems to corrode the electrical grids? I think you're getting tired or loosing [sic] your touch. Could this "builder" be decieving [sic] you with this letter? Apparently you've got his voltage charts to support his letter. Please realize that according to UL1081, we are not allowed to introduce stray voltage into the pool? [Akin to the quote, "Please be advised that as Captain of the SS Titanic, I am forbidden from hitting icebergs".] What is going from the positive electrode is routed to the negative electrode and not into the pool water or any other ground. This is not "electronically" the path of least resistance. Water is a POOR conductor of electricity. There is no tendency for the voltage to stray from the cell to the light ring, handrail or ladder, if the system is operated and bonded properly. The tendency is to find the nearest negative to discharge to, that's usually a inch away, on the negative electrode IN the cell."

Now, this last part about WATER BEING A POOR CONDUCTOR is the funniest thing anyone has ever said to me. While it is true that pure, deionized water won’t conduct electricity, this webpage, for anybody who bought Sean’s hooee and needs straightening out, will explain;

http://msnucleus.org/membership/html/k-6/wc/oceans/4/wcoc4_2a.html

I sited this reference before, in my second blog piece, Why Salt Sucks. It illustrates that "when a salt, like sodium chloride is dissolved in water, the sodium and chloride separate temporarily. The sodium atom will become a positively charged ion and the chloride atom will become a negatively charged ion. An ion is an atom or group of atoms that has a negative or positive electric charge. Negative ions are formed by atoms gaining electrons, and positive ions are formed by atoms losing electrons. Substances that conduct electric current are called electrolytes. They are formed as a result of a dissociation into positively and negatively charged particles called ions."

What this is, is a fourth grade science experiment designed to teach ten year olds "that the ions in the water make salt water an electrolyte. An electrolyte is a nonmetallic electric conductor in which a current is carried by the movement of ions". In the experiment, the children observe that as they begin to add salt to the water, the water begins to conduct electricity, and the light begins to glow. The more salt they add, the more brightly the light glows."

IT IS THE VERY ACT OF POURING SALT INTO YOUR POOL THAT MAKES ALL OF THESE THINGS OCCUR, BECAUSE BEFORE YOU PUT SALT INTO YOUR POOL, YOUR WATER WASN’T AN ELECTROLYTE. IT WAS JUST WATER.

Sorry for shouting. I just really want to get my point across to you about this. And I’m not shouting at Sean. I’ve accepted the truth in the statement, "it is difficult to get a man to understand something when his salary depends upon his not understanding it." This enables him to believe that salty water is a poor conductor of electricity.

On the subject of stray currents, he had previously written that, "our manual also states that the installation should be performed by a licensed electrician, whom we assume should know to bond the equipment, so stray currents/voltage are not a problem... When a pool is not bonded properly, or if the installation of the salt system... is NOT installed according to the manufacturers instructions and the National Electric Code (NEC) guidelines, it may allow stray currents/voltage into the pool."

Now, you all need to stop and think about that. Who installed your salt system? Was it a licensed electrician? Or was it your pool man? Because if it was your pool man, then AutoPilot is off the hook if anything goes wrong. It says so right in their manual. And that is the point of that statement. To get them off the hook. And to drive that point home, Sean said in another e-mail, "...as a result of... any pool company being able to buy a salt system over the counter at their local distributor, and not knowing anything about it, reselling it to a pool owner. No training, no education, ignorance. It is a shame."

Pretty scathing indictment of pool supply distribution and local pool companies. Wouldn’t you say? That’s you, Pool Guys. That’s you he’s talking about. Did you know that if you don’t have a licensed electrician do the work, then you’re on your own if anything goes wrong?

On the subject of salt’s corrosivity, he wrote, "as I sweat (which can be up to 9000 ppm salinity) on my elliptical trainer, I don't bother to wipe it down everytime, [sic] so is my persiration, [sic] which also evaporates leaving a high salinity behind, causing corrosion to the metal frame of my elliptical device? I haven't seen any."

So, in Sean’s World, salty sweat isn’t corrosive. All of you Gym Rats out there can tell him different. Right? You’ve all seen the corroded metal from that very thing.

He’s also the fellow who wrote to me and said, "I have to admit and thank you though, as you are causing me to reflect on what I present in my seminars, and am forcing me to research more of the ‘facts’ related to salt levels, such as: EPA standards for the taste threshold for chloride is 250 ppm (I neven [sic] knew this). Although I've also found other sites where it states the salt taste threshold for humans are as low as 50 ppm or as much as 1000 ppm. I've been stating it to be 3500 ppm for years."

Odd. His references tell him that the taste threshold is anywhere from 50 to 1000 ppm, but it’s convenient to use 3500 ppm in training seminars because... hmm, let’s see... could it be because that’s the upper threshold for operating his salt system?

On the subject of the lie that all the salt system manufacturer’s tell that you’ll "Never Have To Buy Chlorine Again", Sean qualifies the lie thus; "To support our marketing statement, if you're producing your own chlorine, why buy chlorine again? Regarding never having to shock your pool again, our Owners Manual states that you may occasionally have to shock your pool, page 12 under chemistry, and page 16 under troubleshooting. Although we recommend a non-chlorine shock (MPS), there's no reason why a chlorine shock should not be used, but using monopersulfate certainly allows the statement to be correct in never having to buy chlorine again, even to shock."

The thing that makes it okay to say "Never Buy Chlorine Again" is that they want you to buy the more expensive non-chlorine shock instead.

So there’s that.

The first time Sean wrote to me, I responded by saying "I don't think we can have much of a dialogue". But he persisted. And he vacillated between being insulting and rude - like the rant that opened this blog piece - to apologetic, like "I apologize for the ‘nasty’ tone of my e-mail" - his very next correspondence, as a matter of fact. But in the end, he wrote, "I think our communication has disintegrated" and swore never to write to me again, sorta like, "well, you won’t have Dick Nixon to kick around any more".

These are the people who are selling you salt systems. Makes you want to run right out and switch over to salt, doesn’t it?

Res Ipsa Loquitur.

Stray Currents Are Dissolving
Your Salt Swimming Pool

I finally see how the manufacturers get away with selling you something that does so much damage to your pool while their sales continue to increase and no one comes along and shuts them down.

It’s because it’s hard work finding out about this stuff. And that’s what they’re counting on. They’re depending on the fact that none of us in the business who work on the user end of these Trojan Horses will have time to do more than bitch to each other about what their product is doing to all the pools, and that you pool owners, since you’re only looking at one pool, won’t have anything to compare it to and won’t ever draw the conclusion that if you get shocked when you reach for the ladder or hand rail and after extensive and expensive troubleshooting an electrician tells you that it’s because your bonding lugs have dissolved off your bonding wire, that it’s all because of your salt system.

I’m a perfect example of that. I looked at these problems and wondered what was going on for a long, long time before I wrote my first blog piece last September. And I wrote it and posted it in pure frustration that, as badly as the pools were dissolving right before my very eyes, nobody seemed like they were even thinking about not selling salt systems to new pool owners. I’d show up at a brand new pool and see about 120 feet of beautiful limestone coping, several hundred square feet of white Mexican travertine pavers, six or eight brass pencil jets or fan sprayers, maybe even one of those really slick high end, brass sheer descents, and a Goldline or Zodiac salt system to go along with it all. I would be standing there looking at what I knew was going to look like the surface of the moon - with copper stains - in a little over a year, and I’d want to cry.

Knowing what I know, how was I supposed to congratulate the new owners on their beautiful new pool and then just keep my mouth shut and take their money for cleaning their pool each week, and then play dumb when they came to me a year later asking me for answers?

As you can see, I didn’t keep my mouth shut. Not only did I start telling my customers what I knew and what I suspected, but I posted a blog piece. One single blog piece. Then, a fella named Baboosa wrote and said, "Nice ! You did that so well and never even touched on the part about galvanic corrosion and how salt systems help sell heat exchangers."

And off I went looking at galvanic corrosion. Which led to looking at sacrificial zinc anodes. Which led back to a harder look at why the limestone and sand stone were being destroyed. Which eventually led to exploding chorinators. Which led... well, the point I’m trying to make here is that every topic, except the first one I posted, has been written as a result of getting an e-mail or a phone call or having a face to face conversation with people in our industry who are just as concerned about all of this as I am. One by one, they said, "Hey, Pool Guy, take a look at enter disastrous side effect here ".

Now get a load of this. Most of them could make more money if they would just keep their mouth’s shut and sell salt systems. None of them are manufacturers of competing products - like ozonators or tab feeders or anything else. They are, almost exclusively, service, repair, and construction folks, and salt pool owners.

Not to say that salt’s competition hasn’t tried to influence me. If you’re a regular reader, I’m sure you remember Jeff Jones’ ill advised e-mails. Then, two weeks ago, Tim Dickson, Director of Business Development for Chemilizer Products thought that maybe I could introduce him to all these pool builders I talk to who have become disillusioned with salt, because he’s just positive that his product is the answer to their prayers. And just this week, Chris Brennan, East Coast Sales Manager for UltraPure ozone generators offered to give me a free unit for "your test and evaluation at no cost".

But getting back to what I started out to talk about. I only get one morning a week to do this blog. My wife likes to sleep in on Sunday mornings - which I’m sure to some of you makes us Godless Heathens, or Seventh Day Adventists. Take a wild ass guess which - so I take that one morning of the week to put down on plasma what has been percolating in my head all week. The process starts with one of you telling me something and then me having that on my mind - like a dog with a bone - as I go from pool to pool all week long. Then I regurgitate it here.

As far as I know, this blog, and two articles in Pool & Spa News, are the sum total of opposition to the idea that salt should rule the pool world. Yet nearly all of us who have worked with salt and aren’t blinded by greed and avarice think it’s the worst thing that’s ever happened to our industry.

And, sadly, that’s why salt sales are still on the upswing. Even when there are builders out there who write me e-mails like this:

"Pool Guy,

I read your material with great interest and wish to encourage you to keep up the fight. I run a reasonably large pool company... that has been building pools... for 30 years. We started using salt systems about 15 years ago when they were in their infancy (we tend to be front runners on pool issues). We started with units like the Lectronator and other arcane units. During [a] 15 year period... almost every [in-ground vinyl liner] pool we built (about 200 a year) had a salt system on it.
My indoctrination was in the form of countless service calls for staining, [electrical] shocking, and a host of other "unrelated" issues. I spent a year tracking complaints, making voltage checks, resistance checks, breaking down different units into its components and so forth. What I found was exactly what I expected given the construction of this system in the form of a battery. What I could not understand was the industry manufacturers with their (what I understand now to be scripted) answers to my problems. As you say, it ranged from "grounding issues", improper materials, low grade stainless, and on and on. Especially frustrating was that we all knew how long we had been in business and that the only common denominator [to all these problems] was the salt system. By the time I had amassed my data, based on the soil type and condition of an install, I was able to tell the manufacturer of the last generator we were using what the stray voltage amount would be and how long before the stains and corrosion would appear. Like I said, we tried [5 different major manufacturer’s salt systems]. In the end, we decided that there was insufficient profit in pursuing what was clearly a damaging component.

Over the years, we have dealt with all manner of product that has one or more detrimental effects on a pool. But not until these salt systems had we encountered a unit that deals a blow to the entire pool. I think the biggest single factor was the propensity to negatively effect the grounding system around the pool. The stray current in the system created an environment where the grounding lugs would corrode off and leave large portions of the pool disconnected and very prone to shocking our customers. Whether it was hand rails or coping sections, it made the whole pool experience less inviting.

It is nice to see that the rest of the industry is finally learning what we already know--salt systems are evil. What is going to suck for everyone is when customers discover that these are known problems--it might be a tobacco settlement fight scenario with everyone wanting to be made whole."

So, you can start to see how this blog really isn’t written by me. I mean, if I was on my own here, the only experience I’d have to call on are the pools I see. And I would never hear about stuff like this. Neither would you, for that matter. That’s why things like this blog and the few truly open pool forums out there are so important. This is a perfect example. Here’s a guy who did a yoeman’s job to support a new technology for fifteen years, at great expense to his company. All along the way, he documented his problems and tried over and over again, with five different salt systems, to integrate them into the pool environments he was building. To no avail.

And here’s why: Ohm’s Law

http://en.wikipedia.org/wiki/Series_and_parallel_circuits

If you never took a course in basic electricity, then reading about parallel circuits at Wikipedia won’t really help you understand what’s going on. But if you think of it as a plumbing situation, it’ll be easier to see. Electrons, like water, follow the path of least resistance. If you have a big pipe and you’re pushing water through it, then you’ll have 100% of the water come out the other end of that pipe. If you plumb a bunch of tiny pipes, even as tiny as a strand of hair, onto your big pipe then some of that water is going to follow the path of least resistance and flow down those little pipes, too. Granted, almost all of the water is still going to come out at the end of the big pipe, but some will be lost down those little pipes.

Now, think about your salt cell. What we’re doing is literally jumping current flow from one cell plate to the other using salty water as our conductor. You see, the salt not only makes the chlorine, but it makes the water more conductive - turns it into an electrolyte - so that this whole thing can happen. Think of that gap between the plates as our big pipe. Most of the current flows harmlessly from one plate to the other. Now, think of the distance from those cell plates and your heater heat exchanger as one of the little tiny pipes. Some of the current is going to flow there.

It Has To. It’s Ohm’s Law. It’s The Way Things Work. It’s Science.

And this is also where our old friend Galvanic Corrosion comes into play.

http://thepoolbiz.blogspot.com/2006/10/why-salt-sucks-so-do-i-have-your.html

Depending on how anodic or cathodic on the Galvanic Index the metal is, that will determine how big it’s tiny pipe is. Like Tim Mott at Pool Plaza said about the salt system blowing through the guy’s stainless steel filter in one month.

http://thepoolbiz.blogspot.com/2007/02/comments-lost-in-shuffle-i-have-posted.html

The filter tanks are stainless, way up the list from titanium on the Galvanic Index, and the filter tanks aren’t grounded. They bear the whole brunt of the Stray Current and Galvanic Mismatch Attack. The light rings are next, because they’re stainless, too. But they’re grounded and so they last longer. The heaters are next up because copper is closer to titanium and so presents less of a difference of potential. But it still makes a tiny pipe and draws a little current. If the heater is properly grounded, then most of the current is shunted to that bare copper bonding wire, and it flows down that wire to the, oops, brass bonding lug, another Galvanic Mismatch, where the induced current flow causes Galvanic Corrosion to accelerate in proportion to the amount of the Stray Current. Eventually, you disintegrate the lug or the wire. Then, nothing is bonded to earth ground. Now we kick the damage done by Stray Currents into high gear. The metals can’t shunt the current flow to their bare copper bonding wire, because it’s not grounded any more, and the metals bear the full brunt of the attack like the ungrounded stainless steel filter tank did, and they start to disintegrate.

You can go right down the list of the metals that have to be in your pool and pretty much predict which metal will fail first and last. That’s why the heater manufacturers are changing from copper to cupro nickel headers because, once again, it’s closer to titanium on the Galvanic Index. Mostly these days the only reason they use metals at all is because they haven’t figured out how to build a plastic heat exchanger that won’t melt. And they don’t know how to conduct electricity through plastic, either.

But, hey, how much current are we talking about? I mean, the current flow between the plates must be pretty small to begin with. Right? Well, Goldline, which is the only one I could find who publishes the current flow for their cell, puts it at 4.5 to 7.8 amps, using 22 to 25 Volts DC.

According to this guy;

http://www.mikeholt.com/documents/powerquality/Shock_Stray.pdf

"The majority of people can feel 0.003 to 0.004 amperes". This is a research paper about the electrical shock hazards due to Stray Currents. So 7.8 amps, the max current flow between a salt cell’s plates, is 2,600 times more than the 0.003 amps, or 3 milliamps, that you can feel. And if I remember my US Navy Basic Electricity and Electronics Ratings Course, 10 milliamps is enough to cause paralysis and 100 milliamps is enough to kill you. That’s one tenth of one amp, and we have 7.8 of them.

Now, I’m not saying that people are dying by the bushel basket in salt swimming pools. I’m saying that there are, by the immutable laws of physics, Stray Currents that go hand in hand with a salt system on your swimming pool. And I’m saying that over time, those Stray Currents will cause deterioration of the grounding and bonding of the other equipment that supports your pool and will cause damage to the bonding connections which keep your pool safe to swim in even though it’s operated with electricity for everything from your pump to your heater to your lights.

The definition of Stray Currents is electrical current through a path other than the intended path, these unintended paths being those little pipes branching off of the big pipe. According one website:

"Stray current corrosion results from (direct) current flow through paths other than the intended circuit. For example, by any extraneous current in the earth. This type of corrosion is sometimes also called "electrolysis" , because of its mechanism.... Generally, stray current corrosion is caused by uncontrolled electrical currents (DC is most harmful) from extraneous sources through unintended paths... These are mostly the result of bad earth return on electrical equipment, giving rise to leakage of currents through metal structures and other preferentially conductive paths... If current passes in and out the metal structure, an electrolysis cell is set up (hence the name: ‘electrolysis’ sometimes used for stray current corrosion). As a result, the area where the positive current exits the metal structure is forced to react as an anodic site. This causes the local oxidation (corrosion reaction) of the metal piece, which may lead to a rapid consumption of the metal and, eventually, to a complete penetration of a metal wall (e.g., from a pipeline, etc.)."

When you read this, it makes you realize that installing a salt system on a swimming pool and then pouring salt into the water is the only way that you can make this type of corrosion attack a swimming pool. Salt Cells use DC current, and like the paragraph above says, "DC is most harmful".

Of course, if you ask a salt system manufacturer about Stray Currents, they’re going to tell you that they don’t exist. Because in the Land of Sales & Marketing, the Laws of Physics are suspended until your check clears.

But if that’s true, then why is the Pool Tool Company, an outfit that’s been making special tools for us Pool Guys for more than 35 years, doing a land office business in sacrificial zinc anodes? To quote their page, the in-line zinc anode is:

"A Must For Salt Water Pools

[Stops]

Plaster Discoloration
Metal Erosion
Heater Damage
Black Stains Around the Pool Light

The in-line zinc anode is attached to the bonding wire thereby protecting all metal parts against the effects of electrolysis. The see-through housing allows the anodeto be easily replaced when depleted."

They sell two other sacrificial zinc anode products, both designed for use only with salt pools. See for yourself:

http://www.pooltool.com/index.php


Yet salt system sales continue to rise. Because there’s hundreds of Them working long days every day to tell you why you Just Gotta Have Salt! While there’s only a few of us who manage to get a few hours a week to try to tell you that you’re better off drilling extra holes in your head than you are blowing twelve hundred bucks on a salt system.

But if the builder who sent me that e-mail is right and enough independent research gets done to prove that the manufacturers had to know about these problems, then the fit really will hit the shan. He also sent me some of his comparison voltage readings between nearly identical pools, one with fresh water and one with salt, and next week I’ll post those along with some readings I’m going to take on my pools.

This is all I have time for this week and I know it’s beyond plenty to read and digest. The fact that it's too much is, after all, what they’re counting on.

Maybe somebody else could start another salt blog and lend me a hand baling all this salty water. I’d really appreciate it.