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Video:How to Test Pool Water

with Scott Schmitz

Testing and balancing the water in your swimming pool is not only essential to the pool's finish and filtration system, but also greatly affects the health of your skin and eyes. Learn the simple steps to test pool water.See Transcript

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Transcript:How to Test Pool Water

Hi, I'm Scott Schmitz with All American Custom Pools and Spas in Norwalk, Connecticut for About.com. Today we're going to show you how to test and balance your swimming pool. Testing and balancing your swimming pool is essential for the long life of your finish, the filtration equipment, the health of your skin and eyes.

Test the Pool Chlorine

The first test he's going to be doing is of the free chlorine - that means the effective chlorine, the stuff that kills the bacteria. He's going to take a water sample from approximately eighteen inches below the surface. You do this on every test. The reason you do it is because you don't want a topical reading. When Robert adds this reagent, when he adds this to the water it's going to change a color. What this test kit is telling him is between 1 part per million and three parts per million is the ideal amount of chlorine. Three parts chlorine per million parts water, that is ideal, whatever you did the week before you should continue.

Test the Pool Water PH

What he's going to test right now is PH, the positive hydrogen of the pool water. It's important to keep your ph in balance. That means between 7.4 and 7.6 parts per million. This kept in balance will be ideal for your skin, your eyes, also the pool finish and equipment. If the pool is too acidic the water is corrosive - it could pit the finish your plaster finish. It can harm your vinyl liner finish and make it brittle. It could also have a very negative effect on things that are copper - such as your swimming pool heater. And it will force erosion of your heat exchanger way before its time.

Notice that he's completely inverting the test. You have to drop it straight down, not at an angle. Also, take note that he's using the cap and not the palm of his hand to mix the chemical. Your ph and your skin could affect the reading, so you don't want to use your hands to establish what the water test is. Robert's test showed that the ph in the swimming pool water was 7.8 parts per million. Although that's not too bad, we want to lower that to an ideal reading of 7.4 or 7.6.

This particular test kit that we're using gives us something called an acid demand which allows us to simply tell us, by drops, how much acid we should put in the swimming pool. Depending on how many drops he gets to change the color to ideal will determine how much acid or ph minus we need to put in the swimming pool water. It took Robert two drops to turn his PH reading from 7.8 to 7.6, which is ideal.

Use the Water Test Kit Chart

There's a chart in all these test kits that'll tell you how much product to put in. So this chart is going to tell us how much dry acid or muriatic acid to use to balance the ph.

Test the Water Alkalinity

What Robert's going to be testing right now is the total alkalinity of the swimming pool water. It's important to test the alkalinity because the balanced alkalinity keeps the ph from jumping high and jumping low. And, what he's adding right now is a chlorine neutralizer. He doesn't want the chlorine that's established in the swimming pool water to affect his alkalinity reading.

This test that he's doing right now is slightly different from the other ones in that you don't cap it and mix it. It's called a titration test. All test kits are kind of different so the colors that you'll be comparing are slightly different. This one is supposed to change from that color blue to clear. And he's going to be adding those drops one at a time until the water turns clear. This is called titration.

You'll notice that its completely changed color - which is what Robert was looking for. Robert got 12 drops, which means that it's 120 parts per million. Ideal.

Balance the Swimming Pool Water

Ok, so we've just tested the swimming pool water and now we want to balance it. All of the products quantities and amounts are listed in the instructions. You need to read the instructions for whatever test kit you have. And I also recommend that you consult a pool professional once a month.

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