How to Take Your Pool Water Testing to the Next Level

You’ve opened your pool, and you’re looking forward to long, lazy afternoons relaxing in the crystal clear water. Or maybe you’re planning a big pool party for friends and family. But is your pool ready? The best way to know is to test your pool water.

You already know how to test your pool water for chlorine levels and pH balance, the primary components of ideal pool water. But what about other potential contaminants? If you’re not testing your pool water for copper, iron, and calcium, you’re leaving your pool vulnerable to potential damage, not to mention an unsightly appearance.

What about phosphates? Should you be testing for those? And if you have a salt water pool, testing for salt levels is vital to your pool’s health.

Let’s take your pool water testing to the next level with an in-depth look at what chemicals and minerals to test for and why, how often to test, and what to do if levels are too high—or too low.

Testing for Copper: Getting Rid of the Green

If your pool water is cloudy, or you have greenish or black stains on your liner, copper is a prime suspect. Copper buildup usually happens for one of two main reasons.

First, the tap water you use to fill your pool may contain trace amounts of copper. As water evaporates from your pool, it leaves the copper behind. The less water in the pool, the higher the copper levels.

To counter evaporation, you’ll add more water, which means you add more copper, and then more water evaporates, and that leaves—you guessed it—more copper in your pool.

Second, low pH levels can cause copper elements in your pool filter or plumbing to corrode. The corrosion will then make its way into your pool water. The longer the corrosion is left unaddressed, the more copper buildup you’ll have in your water.

Greenish stains on the pool walls and floors may be an indication of too much copper in your pool water.

Greenish stains on the pool walls and floors may be an indication of too much copper in your pool water.

How to Test Your Pool Water for Copper

Most test strips don’t test for heavy metals. You’ll need a special set If you click this link and make a purchase, we earn a commission at no additional cost to you. in addition to the ones you use for, chlorine, pH, and other levels. The good thing is, they’re pretty inexpensive.

How Often to Test for Copper

While it’s ideal to test chlorine and pH levels weekly, it’s sufficient to test for copper once a month. Testing your water on a regular basis will keep copper levels at bay before you even see its effects. This will mean less work for you as you won’t have to remove liner stains on top of addressing the copper in your water.

In addition, because low pH levels can contribute to high copper levels, it’s essential to test them weekly. Keep them under control, and you may be able to avoid copper buildup altogether.

How to Fix High Copper Levels

After testing your pool water, if you do find it contains a high level of copper, you have a couple of options to remedy it.

Metal Sequestrant

This is a substance that forms chelate complexes with polyvalent metal ions, especially copper, iron and nickel, to prevent oxidation.

In plain English? A metal sequestrant binds with certain metals in your pool water and keeps them from rusting, which is the cause of those greenish or black stains on your liner. It’s usually a liquid you add to your pool water.

Be aware that a sequestrant does not remove copper from your water—it simply keeps the copper from staining your liner. Also note that sequestrant breaks down over time.

If high copper levels are due to the element being present in your tap water, you’ll need to add sequestrant on a regular basis to prevent stains. It’s best to follow the instructions on whatever sequestrant you choose. You may also want to find out what chemicals and minerals are present in the water where you live.

Metal Trap Filter

This is exactly what its name sounds like. Much the way your regular filter removes debris and other undesirable substances from your pool, a metal trap filter grabs hold of metal in your pool water, thereby removing it.

A metal trap filter selectively filters out metal, so it’s not meant to replace your regular filter. It’s also not a permanent piece of equipment. You’ll set up and use the filter to remove the metal from your water, and once the process is complete, your pool water should be free of metals.

Note that metal trap filters are sized by the number of gallons they need to filter, so be sure to choose one that can accommodate the volume of your pool.

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Testing for Iron: Banishing the Brown

You walk out, all ready to dive into your pool and cool off—and find the water is brown or rust-colored. Gross! No one wants to jump into that. Sounds like you may have too much iron in your pool water.

Just like copper, iron levels can rise if your pool water’s pH balance is low, so there’s another good reason to make sure you’re testing pH balance on a weekly basis.

Also, if you get your water from a well, it may have higher iron levels than tap water which, in turn, will mean high iron levels in your pool. And as happens with copper, as your pool water evaporates, the iron is left behind only to increase each time you add water to your pool.

If you’re unsure of the minerals present in your well water, you can test it, or have it tested by a certified water testing lab in your state.

How to Test Your Pool Water for Iron

Usually, the same kit that tests for copper will also test for iron. It just makes sense as both are metal elements. The only difference will be that once you’ve filled the test tube with a sample of your pool water, you’ll add a special solution made to test for iron. Then compare the water color to the color coded chart included with the kit.

How Often to Test for Iron

Obviously, if your pool water has turned brown or rusty, you’ll want to test it for iron levels. But testing for iron once a month—at the same time that you test for copper—will help you monitor levels on an ongoing basis, and keep the water clear and beautiful. It’s all about prevention.

How to Fix High Iron Levels

Again, because they’re both metal elements, the same remedies to fix high copper levels will also work for high iron levels.

You can use a metal sequestrant, which won’t remove the iron, but will keep it from rusting and staining your pool. Just remember sequestrant will dissipate, so adding it must become part of your regular pool maintenance.

Also, controlling pH levels can help control iron levels, so keep a good handle on those.

Finally, a metal trap filter works just as well for iron as it does for copper. So if your water has turned a yucky brown color due to high iron levels, don’t worry. It’s fixable.

Testing for Calcium: Softening the Hardness (and Vice Versa)

Whether water is hard or soft is determined by the levels of calcium and magnesium in it. Depending on where you live, you may have to deal with the problems created by hard water.

If you get calcium buildup in your faucets and showerheads, imagine what it’s doing to your pool filter and pump. Not only that, too much calcium in your pool can cause cloudy water, rough pool surfaces, and heater inefficiency.

But unlike copper and iron, it’s also possible for calcium levels to be too low. With that comes a host of other problems including pitted concrete pool surfaces (including your pool deck), dissolved concrete and grout, and etched plaster. Over time, these can become expensive problems to fix.

Keeping calcium levels balanced is essential to prevent damage to your pool and its surroundings, and to save you money.

A calcium imbalance can cause deposits, dissolved grout, and other expensive damage.

A calcium imbalance can cause deposits, dissolved grout, and other expensive damage.

How to Test Your Pool Water for Calcium

The total hardness (the measurement of both calcium and magnesium salts) level in your pool should be somewhere between 200 and 500 parts per million (ppm). A professional-grade pool water testing kit is going to be your best friend. The best pro kits will test for calcium levels along with chlorine, pH, copper, iron, and other substances.

You’ll simply add a chemical indicator to a small sample of pool water and compare the water color to the included color-coded chart to determine whether your pool water’s calcium is too high or too low.

How Often to Test for Calcium

If your pool water becomes cloudy, or you start to see scaling on your pool liner, or you notice any pitting in the concrete in or around your pool, it’s definitely time to test for calcium. At that point, though, you’re a little late to the party.

To stay on top of things, prevent damage, and save yourself from having to make expensive pool repairs, test calcium levels at least once a month.

However, if you live in an area where the tap water is either hard or soft, or you get your water from a well that has a high level of calcium, you may want to test more often, maybe every two weeks, or even once a week just to be on the safe side.

How to Fix High Calcium Levels

You have three options here.

Replace Some of the Water

If your water source isn’t hard, and your pool’s calcium level has risen due to other factors, you can drain a few inches of water from your pool, and replace it with softer water.

Use a Flocculant

When added to your pool water, a flocculant will attract the excess calcium and cause it to clump, making it easier to remove. Once the flocculant has worked its magic, clean your pool’s floors and walls to remove the calcium. Then backwash your pump filter, and clean it.

Use an Acid

If the first first two options don’t work, you can try adding dry acid or muriatic acid to your pool water. This will not reduce the water’s hardness. Instead, it raises the saturation level, which will help to balance the water.

How to Fix Low Calcium Levels

This is a much easier task than lowering the amount of calcium in your pool water. If calcium levels are too low, simply add calcium chloride to your pool. How much you add will depend on the size and volume of your pool, so follow the manufacturer’s instructions carefully.

Once it's established itself, algae can be very tough to get rid of.

Once it’s established itself, algae can be very tough to get rid of.

Testing for Phosphates: Do You Really Need To?

Harmless and so ubiquitous they can be found in everything from pharmaceuticals to cleaning products to fire extinguishers, phosphates are essential to our everyday life.

The truth is, phosphates are not a problem for your pool water.

You may hear that phosphates are a problem because they serve as a food source for algae, which can have a tremendously negative effect on your pool. But killing its food source is not an effective method of controlling algae.

How to Test Your Pool Water for Phosphates

You really don’t need to. Your pool will always contain phosphates, no matter what you do. That’s normal. They find their way into your pool via dirt, twigs, and leaves that fall into the water, sprinkler runoff, or even fresh water used to top off your water levels to counter evaporation.

How to Fix High Phosphate Levels

Addressing this issue—and more importantly, the problems it can lead to—actually isn’t a matter of reducing phosphates.

The key to controlling algae is prevention, usually in the form of algaecide.

You’ll also want to make sure your chlorine levels are stable, and that your pH and alkalinity levels are correct. Keeping those three things balanced will go a long way to preventing algae from taking over your pool and turning it into a black lagoon.

It’s also important to note that adjusting your phosphate levels will not get rid of algae once it’s formed. Once you have algae in your pool, you must take steps to kill and remove it.

Again, it’s about addressing the algae directly, not the phosphates.

Testing for Salt: Keeping the Chlorine Flowing

If you were lucky enough to find a home with an existing salt water pool, or you’re thinking about converting your pool to salt water, you’ll need to add testing for salt levels to your regular pool maintenance schedule.

Just like calcium, salt levels can be a problem whether they’re too high or too low. Too much salt can throw your salt water chlorinator into overdrive.

Too little salt is even more important to address because it has an effect on how clean your pool is. Your pool’s salt water chlorinator requires salt to produce chlorine and keep your pool clean and sanitary.

If there’s not enough salt in the water, you won’t have enough chlorine, and this can present problems not only for your pool, but for those swimming in it.

Balanced salt levels are essential to chlorine production to keep your salt water pool clean.

Balanced salt levels are essential to chlorine production to keep your salt water pool clean.

How to Test Your Pool Water for Salt

To keep your chlorinator running well, and your chlorine at optimal levels, you want to shoot for a salt level of approximately 3,200 ppm. Once again, specialty test strips are the fast and easy method to determine pool water salt levels.

Using them is a simple matter of collecting a water sample in a test tube, dunking a dry test strip into the tube, removing it, and waiting about 20 seconds for the results.

How Often to Test for Salt

Because it’s not as delicate to keep balanced as other chemicals and substances in your pool, salt can be tested just once a month.

However, you may want to test salt levels after certain events such as a rainstorm, adding fresh water to your pool, or after you’ve had a lot of guests swimming and splashing around in the pool.

How to Fix High Salt Levels

To prevent your chlorinator from having to work too hard to assimilate an overabundance of salt, it’s a good idea to reduce too-high salt levels. You can easily accomplish this by draining a few inches of water from your pool, and adding fresh water to bring the level back up.

Retest, and continue the process until salt levels are back in the optimal range.

How to Fix Low Salt Levels

If you test your pool water and find that salt levels are too low, you’re in luck. This is quite possibly the easiest problem to fix with a salt water pool. All you need to do is … add more salt!

Add a little salt, wait a few hours for it to dissipate, then retest your pool water. If salt levels are back to normal, you’re done. If they’re still too low, repeat the process until you get the result you need.

Are You Ready to Take Your Pool Water Testing up a Notch?

If all you’ve been testing for is chlorine and pH, it’s time to broaden your testing range. All of these additional substances are simple to test for, even if you’re a novice pool owner.

With instant test strips, easy-to-use liquid test kits, and a little discipline in your maintenance schedule, you can take control of your pool water, prevent a lot of problems and expense, and keep your pool beautiful and swimmable all season long.

Happy Swimming!

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