Away With Stains

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After getting stains out of swimming pools for 20 years, Jack Beane, owner of Jack's Magic, says, "There's only two types of pools: Those that are stained and those that are going to stain." Perhaps not every pool is doomed to be stained, but if not properly cared for, pools and their surfaces will likely succumb to staining.

But all is not lost. A pool treated and maintained with a sequestering agent from day one stands a fighting chance of never staining. Following, a few industry experts and veterans explain how stains get in pools and how to prevent and treat them.

Search High And Low

Metals that can end up staining pools and spas come from a wide variety of sources, but one of the most likely culprits is the fill water. Says John Puetz, vice president of research and development at Advantis Technologies, "Fill water can contain copper, iron and manganese, and those are the three most common that cause staining.

"Generally speaking, when those are present in the source water, we can test for them. Tap water samples will tell us they're in there and we know what to do to manage them.

"However," continues Puetz, "it is also possible for those metals to be present in the fill water even though when you tested the tap water, they weren't there. For example, sediments can build up in pipes in our neighborhood distribution systems, and those sediments can contain metals. Normally, the demand is what is considered to be a relatively low flow: we're taking showers, we're washing clothes. But if you fill a 20,000- or 30,000-gallon pool, you're now pulling a large volume of water out of those distribution pipes, and you can stir up those sediments. So even though when you took a tap water sample and no metals turned up, now that you've pulled 30,000 gallons of water out of those pipes, you may find some metals that were in those sediments are now in your pool."

Other sources of metals include:

OPEN-AIR RESERVOIRS. Openair reservoirs treated with copper to get rid of algae, and the misuse of a copper algaecide are two other possible sources of metals, says Puetz. "Copper algaecides are rarely by themselves causes of staining. However, application rates of copper algaecides could be. For example, if you buy a typical polyquat algaecide, the application rates on it are relatively high. The rate could be 12, 16 or 24 ounces per 10,000 gallons, depending upon its strength. So if consumers who have been using that purchase a copper algaecide for the first time, and don't notice application rates on copper algaecide are about 1.5 to 2 or 4 ounces per 10,000 gallons β€” substantially less β€” they may put a huge overdose into the pool. So using copper algaecides in themselves is not bad, but if you use too much, that could be."

EQUIPMENT. "When water is aggressive, then it breaks down the metal parts in heaters and sanitizers, and deposits those into the pool," says Jon Temple, owner of Tempool in Jacksonville, Fla. Or, if the velocity of the water running through the pool system is too high, says Beane, metals can be stripped from equipment and end up on the walls of the pool.

CORROSION. If the pool is not properly grounded, this can result in unwanted metals in the water, as well. "It's called galvanic corrosion," says Beane. "Any time you have dissimilar metals and high conductivity, you're basically creating a battery, and you can actually generate electrical current. The softer metal starts going into solution and then it can combine with a carbonate or an oxide and re-precipitate on the finish."

FERTILIZERS. Most lawn fertilizers are iron-based, says Beane, and if any gets in the pool, that can result in a stain. "Also, fungicides used to spray trees, like fruit trees, are generally copper based, and you can get overspray into the pool."

SCREEN ENCLOSURES. "When wind blows through the screen, the screen grabs all the chemicals in the air from mosquito control to fertilizer," says Temple. "They can spray the yard on the other side of the lake and the wind can carry it to your screen, and it'll dry on your screen. Then, when it rains, the rain will wash the screen off and all that goes into your pool."

NEW SHINGLES. These often have a residue on them that can wind up in your pool after it rains, says Temple. "You can get some iron, some zinc, some copper. Most shingles are petroleum-based products, so those carry every kind of metal there is," he says.

PAVER DECKS. If there is sand between the pavers, this can also lead to staining, adds Temple. "You can get a lot of sand in your pool, and that sand carries an iron."

TINY PIECES OF METAL. Even something as small and seemingly innocuous as a paper clip can leave a stain. Or if someone tosses in a nutand-bolt type washer to dive after and leaves it there, that can lead to staining, says Puetz.

An Ounce Of Prevention

Since pools stains come from so many sources, and can creep up on even the most diligent homeowner or service tech, trying to prevent stains is really the most efficient approach to dealing with this unsightly issue.

Prevention starts at start-up. "Whenever you're filling a pool or adding a substantial amount of fill water, like for a spring fill up, add a sequestering or chelating agent," says Puetz. "The best way in the world to avoid stains is to prevent them. I've talked to more than one builder or service guy who starts up a beautiful, new white plaster pool, and after they fill it up, they hit it with chlorine and it turns colors because metals are present in the water and they didn't know about it. The next thing they know, they've got extremely discolored water or worse β€” staining on the surface. Can you imagine. You've got a customer that just wrote you a check for $45,000 for their nice, new pool and you stained it. They're not going to be happy and you might have to acid wash."

Beane also believes it's important to use a sequestrant when starting up or filling a pool. "It's such cheap insurance against having a finish problem and having to do warranty work on a finish that the majority of companies that are building pools and the majority of plasterers plastering pools today use some type of stain prevention."

Jon Temple certainly does, but he does much more than just add some chemicals before handing the pool over the homeowner. "I take care of my pools for 28 days because the biggest percentage of stains are caused by incorrect start-up, which would be incorrect chemistry for that pool within the first 28 days after the pool is finished and filled," says Temple. "Out of all the stains I see, 90 percent of them are from calcium, from scale. These stains are from incorrect water balance to where you have a high pH and it makes the pool scale over.

"I believe it takes 28 days of more attention so you don't have this scaling issue or problems in the future. But if you're building 500 pools a year, to maintain them for 28 days after start-up, you have to get the homeowner more involved. I don't trust homeowners to do exactly as I tell them, so I follow up behind them to make sure they're doing their job.

"I'm more expensive," Temple continues, "but I'm going to maintain the pool for a month after it's done because that's the most critical time where staining occurs. And by the time we give you your pool, the curing process is close to over, all the metals are out of your pool and there are no stains in your pool."

Handing homeowners a pristine pool is essential for generating referrals. Says Beane, "The chances of a builder ever making a homeowner totally happy to where he is referring the builder to his neighbors and friends becomes very remote the more finish problems he has."

It's not only critical to use a sequestering or chelating agent at start-up, it's also important to use a regular maintenance dose. "We understand that sequestering agents expend themselves as they do their job," says Beane. "So as they're capturing contaminants and filtering them out, they're going away, just like chlorine goes away, depending on the demand. And every pool has a different demand."

So to prescribe the same maintenance dose for every pool wouldn't make sense, but every pool should get more sequestrant as the season progresses. "We have a Sequestrant Test," adds Beane, "that allows dealers or homeowners to test their water to see if they need to add more." Though Beane says there are homeowners who use the Sequest Test regularly, Jack's Magic gears the test more toward dealers and service professionals. "It does a couple of things," notes Beane. "It keeps the store in contact with the homeowner and it helps keep the finish looking the way the homeowner expects it to."

Without a sequestering agent in the water, even a pool with balanced water can suffer staining. "Poor water balance can accelerate the evidence or appearance of staining," says Beane.

"But you can have perfectly balanced water and stain the finish completely."

And it happens for the same reason it happens at start-up: if there are metals in the water but no sequestering agent, and the pool gets shocked, the oxidized metal ions can precipitate and adhere to the finish.

"It takes much smaller amounts of a sequestering agent used regularly to prevent staining than it does to remove stains when they do," says Puetz.


If preventative measures are not taken and you're faced with removing a stain, there are a few options, and exactly which one you should choose depends on how extensive the staining is. If most of the pool surface is stained, an acid wash may be the way to go.

Or perhaps the staining is not quite so extensive, but the cyanuric acid or TDS level is too high and you have to drain a large percentage of the pool water to get the CYA or TDS back in range. In this case, acid washing may be an appropriate solution, as well. In general, if the cyanuric acid is above 80 ppm, you need to dilute the pool to get it back to 40 to 70 ppm, and if TDS is above 4,500 ppm, the pool needs to be drained until the TDS level is 1,200 ppm or lower (on nonsalt systems).

If draining the entire pool for an acid wash is not feasible, consider a light acid wash while the pool is still full. United Chemical Corporation offers a No Drain Acid Wash Kit that it claims will remove stains and can be used by anyone, whether they have prior pool experience or not.

Another option for treating stains while the pool is filled is large doses of a sequestering or chelating agent over a period of several months. This technique is not nearly as quick at removing stains, but can be effective. "The success of this method depends upon how deeply set a stain is, how old it is, how extensive it is, and what the conditions are that caused it," says Puetz.

What are more commonly used today and provide a faster result are stain removal products, like Stain Magnet from GLB, Pool Stain Treat from United Chemical Corp., and The Copper & Scale Stuff from Jack's Magic. When using these chemicals, it's critical to always follow manufacturer's directions. "Each manufacturer has its own set of ways that you should go about fixing a stain," says Temple. "If you try to fix a stain and you have a high chlorine level in the pool, that will create another stain, so you have to follow directions 100 percent or otherwise you can create other problems."

To be sure he's treating the pool appropriately every time, Temple says he always uses a Jack's Magic Stain Identification Kit. "I've been doing this for 20 years, and I test every stain because a Stain ID Kit doesn't cost as much as a new finish does," says Temple. "Some stains look like each other, so if you treat for copper and it's iron, you spent a lot of money to treat that pool, and then you have to turn around and do something else. By the time you put two treatments in the pool, you could mess up the finish to where the pool has to be redone. And that's why you should test. When you eliminate the guesswork, you eliminate a lot of errors β€” and errors are costly."

Conquering Stains

Removing a stain is only half the battle. "The other half of the battle is how do I keep it from reforming," says Puetz. "Because no matter what we do when we take the stain off the wall, unless we're acid washing, if we're keeping the water in the pool, where do the stains go. Back into the water. So now we need to keep that stain from reforming."

To keep the stain from reforming, you'll need to add a sequestering agent. Says Beane, "A sequestrant actually combines with the metal ion and forms a precipitant or a filterable particle that can be filtered out and then you clean the filter and you've eliminated the stain."

In addition, you'll want to continue to add a maintenance dose of sequestrant and try to determine the source of the stain and eliminate that if possible. Also, check to be sure there's a good circulation pattern in the pool.

"It's not uncommon for there to be a dead corner in a pool where staining and dirt accumulates," says Puetz. "If you don't get the water moving into that area, no amount of stain control agent is going to be very helpful."

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