Friday, September 08, 2006
Salt belongs in the shaker. Not in the pool.
Hello? Has anyone noticed what it does to limestone? Travertine? Sandstone? Concrete? Diving board stands? Stainless steel filter tanks? Those little brass handles on the skimmer baskets? Brass pencil jets?
Has anyone noticed how the stainless steel teeth on Polaris 280 drive shafts are eaten down to rusty little nubs in salt pools but not in tablet pools?
Has anyone noticed how filter tank warranties have gone from the typical ten year full or prorated to one year?
Has anyone noticed how every time it rains, if your pool has a tile line drain, your humping salt out to all your pools the next week? Where do you think that salt’s going? But more about that later.
The really hard part to swallow is that the manufacturers aren't admitting any of these problems exist. One time, I asked a manufacturer's rep why didn't he at least tell builders they ought not to sell a salt system on certain pools. We were standing in one of my customer's backyards, looking at one year old decomposing limestone coping at the time.
And this is what he said:
"How can I tell them not to sell a salt system when I don't believe that salt caused this damage. You see, salt is only corrosive at levels above six thousand parts per million and our system only uses around three thousand parts per million. So, to my way of thinking, it's impossible that salty water caused this damage."
I said to him, "We recently discovered this phenomenon that we call evaporation, wherein water, splashed out of a pool onto, say, limestone coping, will actually disappear, leaving it's mineral content behind. Now, we suspect the Sun is the culprit, as the rate of this phenomenon seems to decrease when the Sun Chariot goes behind the hills beyond the edge of town for the night. In the Olden Days, when the magical evaporation occurred, the worst thing we ever saw as a result of the minerals left behind was a chalky white calcium stain.
"But then, we added salt to the mix, and after the water evaporates, the three thousand parts per million salt level is magically transformed to one million parts per million, slightly in excess of the six thousand parts per million you say we need to damage the stone am I going slow enough I realize you're a salesman and so can only speak and not listen but perhaps you can read my lips or think about something besides dollar signs and I've always wondered how do you people lay your head down and sleep at night and what's it like to tell lies for a living and did it ever occur to you to put a moments thought into the handy answers your company feeds you to overcome sales resistance and customer dissatisfaction when a year after your product is installed it's caused upwards of ten thousand dollars worth of damage to a sixty thousand dollar swimming pool and don't you have a decent bone in your body or even a hint of a sense of responsibility to the homeowners, or failing that, to the builders you conned into selling these Trojan Horses along with their otherwise beautiful custom built pools?"
And he smiled and slapped me on the back and said, "Hey, I'm really glad we were able to get together today and brainstorm about this problem your customer is having. It's always such a pleasure talking to you and I'm so glad I was able to come here today and make a difference. Come on and follow me out to my truck. I want to give you some free parts to shut... I mean, to show my appreciation for choosing our products for your customers and to give you some of our brochures about the exciting things we have planned for next season. Real win-win products, because they’re great profit centers for you, and, just like that salt system, wonderful new inventions guaranteed to enhance your customers swimming experience. Like the jagged glass ring toss game that we’re test marketing for next year. I’d like to give you a couple to pass on to some of your better customers...”
Now, I’m just a pool cleaner and repairman. I don’t have the advanced degree in basket weaving or canoeing that is required to even fill out an application for a sales job at most of the Big Three pool manufacturers. But I got tired of watching my pools fall apart and listening to sales reps tell me that the only problem here is that I’m a child of the sixties and, well... you know.
So, I started doing a little research into the possibility that someone out there just might know some of the reasons why I was seeing such heavy damage to so many of my salt pools.
I was bowled over by what a night of Googling revealed.
For example, did you know that:
“Over the past 60 years, concrete infrastructure in cold climates has deteriorated by ‘salt scaling,’ which is superficial damage that occurs during freezing in the presence of saline water. It reduces mechanical integrity and necessitates expensive repair or replacement. The phenomenon can be demonstrated by pooling a solution on a block of concrete and subjecting it to freeze/thaw cycles. The most remarkable feature of salt scaling is that the damage is absent if the pool contains pure water...(and that) ...salt scaling is a consequence of the fracture behavior of ice. The stress arises from thermal expansion mismatch between ice and concrete, which puts the ice in tension as the temperature drops. Considering the mechanical and viscoelastic properties of ice, it is shown that this mismatch will not cause pure ice to crack, but moderately concentrated solutions are expected to crack. Cracks in the brine ice penetrate into the substrate, resulting in superficial damage.”
Oh.... so that’s why the stamped concrete around my customer’s eight pencil jet water features is deteriorating. You see, the first winter after the pool was built, the freeze guard was running the water feature pump every time we got a cold snap. Then, the wind would blow a little bit of the water onto the deck, where it would pool around the base of the brass pencil jets, penetrate the more lightly coated stamped concrete there and cause the damage just like the damage cited in the research study.
On the one hand, I’m just a pool cleaner. I’m sure the builder and the salt system manufacturer thought about all that beforehand and I’m just hallucinating again. And, of course, I have an axe to grind with the builder and manufacturer for screwing my customers like stump-tied sheep. I admit. I’m biased.
On the other hand, the scientists, Dr Scherer and Dr. Valenza, the guys who wrote this research article for The Journal of the American Ceramic Society, have some pretty hefty credentials. Like the Princeton Institute for the Science & Technology of Materials, Department of Civil and Environmental Engineering, Princeton, New Jersey.
Gosh... who should I believe? The guys with the degrees in basket weaving - with a minor in business, of course - or the scientists from Princeton?
Then there’s the article titled “Salt-induced decay in calcareous stone monuments and buildings in a marine environment in SW France”, by a group of six scientists from universities and institutes from Antwerp to Athens to La Rochele, France. The research article matter-of-factly states that “salt-induced deterioration of architectural heritage is considered to be accelerated drastically in marine environments”.
Hmmm... decaying stone... salt-induced... marine environment... What could they be saying? It must be some secret language that only scientists can understand. Certainly the salt, or NaCl, that’s in these marine environments is wholly different from the salt, NaCl, that we dump into swimming pools.
I know. Let’s go to www.saltinstitute.org and ask them.
Wait... what’s this? There appears to be a photo on their home page of salt being harvested from sea water through solar evaporation. Hmmm... I wonder? Could it be that the salt system manufacturers forgot to mention fifty or sixty years of research that proves conclusively that salt hastens the destruction of stone and concrete structures?
But then there’s the article, “The evaluation of crystallization modifiers for controlling salt damage to limestone”.
Ahah! Herein lies hope. These are a couple of different science guys who are talking about adding something to the salt to “significantly affect the capillary passage of dilute and concentrated solutions of sodium chloride and sodium sulfate through columns of limestone.” In other words, reduce the damage of salt on limestone.
They clearly state that “sodium chloride passage through Monks Park limestone gave predominantly subflorescence with mild edge erosion while sodium sulfate mainly effloresced and severely damaged the stone column”.
So, the answer is easy. Just put this additive in with our salt... what is it this wonder additive? Oh, yes, potassium ferrocyanide... Hey, wait a minute. I read somewhere else that they’re already putting sodium ferrocyanide into most road salts and:
“under acidic conditions...this compound is known to break down, generating toxic cyanide forms, including hydrogen cyanide. These toxins appear to have caused serious fish kills as the result of sodium ferrocyanide’s use by the BC Ministry of Forests in fire retardants. Recent animal studies also have shown chronic cyanide exposure may be deleterious to liver and kidney functions and causes both time- and dose-dependent DNA fragmentation, accompanied by cytotoxicity.”
Maybe not what you want your kids swimming around in, after all.
But while we’re on the subject of road salt:
“The corrosion and environmental costs pertinent to road salts amount up to at least $469 per ton on average, and they are often ignored in formulating highway winter maintenance strategies. The magnitude of such hidden costs is significant compared with the nominal cost of using road salts for snow and ice control...”
A ton of road salt only cost about $75.00, or about 15% of that $469.00 a ton. The rest is infrastructure cost. Infrastructure like cars, roads, bridges, the environment. In the US we use about ten million tons of road salt per year. Do the math. That’s $4,690,000,000 a year. If you subtract out the cost of the salt, that means that $3,940,000,000 damage results from road salt.
But I’m sure it won’t hurt your pool, or your coping, or your deck, or your metal water features, or your stainless steel filter tank, or your diving board stand, or the ground around your swimming pool. You see, my salt system salesman told me so. And you can take that to the bank. After all, he did.
Then I read:
“Sodium exchanges easily with calcium and magnesium in soil, as well as other nutrients needed for soil fertility. This process destroys soil structure and fertility. Long-term salt accumulation can cause high soil density and low permeability, which adversely affects plant growth and erosion control.”
You know, that's how water softeners work. They leach the calcium and magnesium out of your water and replace it with sodium. Isn't that great?
Also, think about sodium's effect on your soil the next time you do a cannon ball into the pool. What’s all that salt in the splash water doing to the flower beds? To the grass? To the trees?
Funny story here. Unfortunately, not funny haha. Funny like I wished I could have crawled into a hole when it happened.
Imagine you’re looking out a huge picture window. In the foreground, there’s a beautiful negative edge pool. The edge of the pool appears to waterfall over onto a tree covered hillside gently sloping away from you. There are several trees on this hillside, but the largest and oldest, a huge pecan tree, is smack in the middle of your view, as if this whole project, this whole house and pool and terraces were built centered on that tree’s magnificent canopy.
The water in the negative edge pool doesn’t really flow down the hillside. That’s the illusion. It drops into a trough about six feet below the edge of the pool. That’s where the auto water fill for the pool is installed. When the negative edge pump turns on, it pump water up from the trough, overfilling the pool and creating that illusion. The auto water fill kicks on as the trough drains to make up for any water lost since the last time the negative edge pump was run.
Now, add a salt system. Everything’s fine - except for the water splashed as it falls from the pool into the trough that’s impregnating the ground around the trough with salty water so that no grass grows. But other than that, everything’s fine.
Then the auto water fill gets stuck open. Now the trough overflows. The pool keeps waterfalling salty water into the trough so the water running down the hill has a slowly decreasing saline content. This is about a 40,000 gallon pool, so that’s quite a bit of salty water. If you just poured the undiluted salt granules onto the hillside it would be 1,334 lbs. of salt. Say that to yourself slowly. One thousand three hundred thirty four pounds of salt. Nearly twenty-seven 50 lbs. bags.
But we weren't pouring undiluted salt granules onto the hillside. We were giving the salt the single mechanism it needed to penetrate the ground and saturate the roots of that beautiful pecan tree. We gave the salt water.
Yes. That salt pool killed that magnificent pecan tree. That’s what the arborist said, anyway. He didn’t even know that you could chlorinate a pool with salt when he rendered his opinion, and was pretty well baffled by the idea that a mighty pecan had been felled by salt in Dallas, Texas, several hundred miles from the nearest marine environment and about that far again from any salted winter roads.
That was my first clue that maybe there were going to be “issues” with salt systems.
Think about a good hard rain. You know, the ones where your weatherman says you got a couple or three inches of rain in twenty-four hours. And the pool never overflows because the builder’s a sharp guy who installs tile line drains in all his pools.
Wherever that tile line drain comes out just got about 1,000 gallons of salty water, or about 35 lbs. of salt.
There are so many studies that show significant damage to trees and shrubs and soil from salt. Just google salt damage and plants or trees or soil and you’ll see hundreds of returns of university studies, federal state and local studies, environmental legislation, and more and more and more, all dealing with the down side of too much salt.
If that’s not enough, here’s another one:
The Santa Clarita Valley Sanitation district became concerned because the salinity of the water rose from 129 milligrams per liter in 1997 to 168 milligrams per liter in 2001. The 129 was already far in excess of the 100 milligrams per liter maximum established by the state of California.
The main culprit of this additional salinity was traced back to water softening systems installed in less than 10% of the homes in the water district. So, they banned water softening systems.
Then in November, 2005 they banned any saltwater pools that were connected to the sewer system. In other words, any system that backwashes to the sewer. Salt systems require between 3 and 4 grams per liter to operate. That’s 3,000 to 4,000 milligrams per liter, or thirty to forty times the maximum established by the state of California for potable water. So, you can see why they were concerned.
Now, if they passed that law here in Dallas, Texas, just about every pool with a DE or sand filter would be affected. Because they’re all supposed to be plumbed to the sewer to meet code. In California, though, they’re not required to be plumbed to the sewer. At least according to this guy:
This guy, Harry Clay, isn’t worried about the amount of chloride in the water supply. He’s worried about being able to keep selling them salt systems. And I quote; “With no previous discussion, or input from the swimming pool industry, [editor's comment: industry input? Isn’t that kind of like asking Enron to help the government establish energy policy? Oh, wait a minute. They already did that.] this controversial bombshell caused quite a bit of shock among builders, manufacturers, & salt water pool owners for a few days, until the legs were cut off this ill advised ordinance. The key words to this poorly thought out ruling are ‘Pools connected to the sewer system’. Virtually no pools have been built in Santa Clarita that are in fact, connected to the sewer system.”
You see, Harry’s proud of the fact that in California, they can spray their backwash effluent directly onto the ground. Even though the research shows that “long-term salt accumulation can cause high soil density and low permeability, which adversely affects plant growth and erosion control”.
Because, truth is, most backwash hoses get rolled out to the same spot every time they’re used. So that salty water gets deposited in the same spot every time the pool is backwashed. Too, since they don’t have to plumb to the sewer, they drain pools pretty much wherever they want to out there, depositing anywhere from 500 to 1,000 lbs of salt onto the soil at the end of that drain hose.
Even if they put that hose in a storm sewer, it eventually ends up flushing into a creek or a river, which in turn damages vegetation and the soil.
But Harry’s only concern about putting the salty water in the storm drain is that “storm drains do not run thru the sewer system & are not under the jurisdiction of the Sanitation District”.
Pretty much Harry’s real concern about this “ill advised ordinance” seems to be finding a way to cut the legs off of it, so he can keep selling them salt systems. After all, why should he give a rip about his neighbor’s water quality when there’s money to be made? And besides, he's successful. He and his customers can easily afford the $500 a month water bills the Santa Clarita Water District is predicting if they have to update their equipment to remove the ever increasing levels of sodium in the water. The folks who might have trouble ponying up that much each month aren't in his customer base, anyway.
And I think that’s the thing that bothers me the most about these salt systems. There’s lots and lots of Harry’s out there. Guys who are more than happy to spread misinformation about salt systems for the few bucks they make when they sell them. Misinformation like, “the owners of the technologically superior Salt Water / Saline purified pools don’t flush or backwash their pools nearly to the degree that owners of older pools with the old fashioned chlorine floaters do”.
Honestly, have you ever read anything more ridiculous in your life? No? Then read this; “With the newer Salt Water Purification Systems, we’re using Electrolysis to Oxidize combined chloride molecules & to kill algae & bacteria.”
It’s pretty clear that old Harry doesn’t even know how salt systems work, or when to capitalize in a sentence. He’s turned electrolysis into a sanitizer, instead of what it is in this case; the mechanism that turns a chloride ion into chlorine gas, which dissolves in the water to form hypochlorous acid, the killing form of chlorine.
And the other thing that bothers me is that after all the years of manufacturers and builders ignoring the down side of these salt systems, they continue to stonewall and obfuscate, even as these chickens come home to roost on each and every one of us, as we try to explain to our customer why their pool is falling apart so much faster than their neighbor's pool who doesn’t have a salt system.
Because you already know what the manufacturer and the pool builder are going to say, don’t you?
“It must be your poolman’s fault.”
Great Job look forward to more.
There are very few sanitizing systems that claim they completely replace chlorine. Ecosmarte is the only one that comes to mind, actually, and I've always tempered my enthusiasm about their product by the fact that it's not available - in my world - through the general distribution wholesalers I buy my pool products from. In other words, if it's so good, why isn't it more widely distributed and more easily available?
Chlorine is not ideal. But it is darn near a perfect sanitizer with a very small downside. I would say - from my experience and reading - that in an outdoor pool environment a normal level of chlorine in your pool water is the easiest, safest and most effective way to protect your family.
There is nothing unnatural about chlorine. In fact, the recent craze with salt systems stems from that quest to find a more natural sanitizer, hyped by my industry to make it SEEM like a salt pool isn't a chlorine pool. Truth is, you pour sodium chloride (salt) into the water, it dissociates into sodium and chloride, and then in the presence of sufficient voltage, the chloride ion is transformed into hypochlorous acid - the same hypochlorous acid that is formed when you melt a chlorine tablet into your pool, or throw a bag of granular shock into your pool, or pour a gallon of liquid chlorine into your pool.
Chlorine is so widely used and recognized as an effective sanitizer that sodium hypochlorite - the same compound as liquid bleach - is used in endodontics (root canals).
If dentists are putting it into the deep tissue in your mouth, it's safe to put in your pool water.
You can spend thousands of dollars on "alternative sanitizers", but just remember that the hype for those products - the desire to possess it - is mostly generated by claims made by the people who stand to profit from their proliferation.