Sunday, March 25, 2007
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.
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.
Sunday, March 18, 2007
"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:
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;
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.
Sunday, March 11, 2007
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:
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
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.
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.
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;
"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
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:
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.
Sunday, March 04, 2007
You can tell a lot about a magazine by the flavor of it’s reporting. Give you an example; if I wanted hard news about the state of politics in America, I might read Time, or Newsweek, or US News & World Report, or maybe National Review or Harpers, depending on which way I liked to vote.
On the other hand, if I wanted to know if Britney Spears shaves her pubis, I’d read People or Us or Entertainment Weekly or Hollywood Reporter.
So, anyway, I was reading two of our industry magazines this week; Pool & Spa News and Pool & Spa Marketing.
This week, Pool & Spa News ran a second article about the problems we’re seeing because of salt systems. This new one is called "Coping With Salt" and it shows a two page closeup picture of a single piece of limestone coping that looks much like the surface of the moon. Much like the pictures I’ve been publishing along with some of my blog pieces. The article quoted Greg Donoho, the director for IPSSA Region 9, talking about an eight month old fountain where the coping looked like someone had taken a claw hammer to it.
They quoted Lew Aikens, the owner of Ocean Quest Pools, saying that he’s replaced $100,000.00 worth of Lueders limestone on his projects because of the damage from salt.
They quoted Guy Wood of Westside Pools and Buzz Ghiz of Paddock Pools. They all said the same thing; Salt is ruining our pools.
They even quoted me; "With other products out there, when there was a defect, it would just malfunction or fail. But this is the only product I’ve seen that damaged the whole pool."
They did the Fair & Balanced thing, of course, and allotted about 50% of the article space to the manufacturers so they could tell their lies, like "it must be the homeowners fault", and "3,000 ppm salt isn’t corrosive", and a bunch of guff about everybody ought to start using stronger and more corrosion resistant metals... Wait a minute. If 3,000 ppm isn’t corrosive, then why do we need to use more corrosion resistant metal?
Because they want to have it both ways. They want everybody to upgrade their metals so that they can continue to sell their Pandora’s Boxes, but they don’t want to accept any of the liability for the latent defect that has caused all this damage because they didn’t tell you to upgrade your metals in the first place.
The manufacturer’s also used their interview time to try to foster the myth that every responsible stone mason and pool builder and homeowner has been sealing their stone decks since the beginning of time, and so, you see, they’re not really liable for all the damage to all that stone, like that $100,000.00 that Lew Aikens spent, or the ten’s of millions that will have to be spent nationwide to fix all the failed coping and decks.
And it is a myth that everybody has always sealed their stone and concrete. I’ve been walking on concrete and stone pool decks every day for 28 years, and the only ones I’ve ever seen that might have benefitted from sealing are the ones that disintegrate on salt pools.
But that’s what the manufacturers are trying to do now. They’re playing a waiting game; "The group (of seven manufacturers) plan to conduct research on the topic and have it available by next pool season". The way this game works is you delay, and while you’re delaying, you send your army of reps out there saying the same things over and over again. Things like, "we should be sealing all stone and concrete on every pool anyway", and "we ought to be using marine grade stainless steel anyway". And then, by the time you release your research, you’ve changed the perception of what the problems were to begin with and you’ve got people thinking that it was their own damn fault for not sealing everything like they were supposed to. And why were they such cheapskates as not to afford their customers the benefit of marine grade stainless steel?
But you really have to give Pool & Spa News huge kudos for trying. I mean, they have to do the Fair & Balanced thing. All News Organizations do. And just think where we’d be if we didn’t have Pool & Spa News and people like Rebecca Robledo to bring this discussion out in the open?
Which brings me to the second article I read this week about salt systems. It’s from Pool & Spa Marketing, written by the editor, David Barnsley. It’s titled Salt Chlorine Generators, A Competitive Alternative to Man Made Chlorine, and it’s billed as the Feature Article. But, just as the term "alternative to man made chlorine" is misleading - as if chlorine generators just fell from the sky or something - this whole Feature Article would be more appropriately set in a box labeled This Is A Paid Advertisement.
For that is surely what it is. I won’t go so far as to say that David didn’t write this ad piece - I’m sure that as the editor of Pool & Spa Marketing he’s quite capable of turning out three or four pages of text - but given the fact that there are so many issues these days with salt systems and that none of them are addressed in this Feature Article, I kind of hope that the manufacturers did write the whole thing for him. Then there would at least be a clear cut reason why the whole four page piece is just a salt system pep rally, nothing more than a marketing brochure for nearly every salt system out there, complete with pictures of all of these systems.
The closest the piece comes to touching on any of the real issues that surround salt systems is near the end where they quote the American Society of Testing and Materials (ASTM) saying "when natural stone is properly treated... it will last indefinitely. If not properly treated natural stone can be very porous and vulnerable to weathering and deterioration - whether the stone is used with a salt chlorine pool or not. It is therefore imperative that pool and spa builders and stone suppliers educate homeowners about the appropriate treatment of any type of stone they should use."
And you see? This is how it’s done. You buy space in a magazine so you can get your word out there, that those dumb old builders and homeowners should have been sealing their stone and concrete all along. And you keep buying that space and saying it over and over and over again.
Pretty soon, it’ll stand proud and tall alongside all the rest of the lies that have been swallowed as the truth, like:
No More Green Hair!
Well Below The Level Of Taste!
Never Buy Chlorine Again!
You Need Only Check pH And Alkalinity Periodically!
You call it a Feature Article. I call it Paid Advertisement dressed up as a Feature Article. Advertising parading as News. And this isn’t the first one they’ve done. If you subscribe to Pool & Sap - I mean Spa - Marketing, look back one issue to their Product Insight piece titled Electrolysis & Corrosion From Chorine Generators. It’s another, "Everything is fine, folks. Go back to sleep." piece. It quotes just enough "industry experts" to sound legitimate. But if you check their credentials, you’ll see that they are, for the most part, reps from the companies selling chlorine generators. Zodiac was heavily quoted and Zodiac had a 1/3 page ad on the last page of the piece.
Next week, I’m going to get back to some of the technical issues with salt systems. I received an e-mail from a builder that just set me on fire again. Here’s a little taste of it before I sign off. He’s talking here about chasing warranty issues on his salt pools over the last fifteen years:
"I think the biggest single factor was the propensity [for the salt system] 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."
And just when I thought I’d run out of bad things to say about salt.