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.