3 Ways how to Test Pool Water (and get correct Results)

As part of pool maintenance, a weekly pool water test is simply part of the process.

It is important to make sure that the pool pH, alkalinity, sanitizer level and concentration of other pool chemicals are in the right range.

Testing the pool water is the basis for making decisions about what chemicals to add to the pool water and at what dosage.

However, many pool owners test pool water the wrong way. Because yes, there is more than one way to test pool water.

And the output for that is always a good water sample.

3 Ways to Test Pool Water

Essentially, there are three ways to test the water in a swimming pool.

• Test strips
• Pool tester
• Have pool water professionally tested

Test strips

For simple at-home testing, test strips are our favorite. This solution is inexpensive and extremely simple.

Using test strips:

1. Take a test strip out of the can.
2. Find a spot in the pool as far away from return jets and the skimmer as possible.
3. Dip the test strip deep under water up to the elbow for a short time.
4. Hold the strip still in the air for 15 seconds. Do not shake off the water running down.
5. Compare the discoloration of the test strip with the color scale on the can.

Different test strips can determine the concentration of different chemicals. The most important values (alkalinity, free chlorine and pH) should be covered by good test strips.

Other strips additionally record water hardness, algaecide concentration, bromine content, total chlorine or heavy metal content.

For regular pool water testing, pool water test strips are a good choice because they detect many chemicals and are inexpensive.

Pool Tester

A pool tester is a more professional approach that is also suitable for home use. When using a pool tester, reagent tablets are consumed and need to be purchased regularly accordingly. In terms of price, pool testers are similar to test strips.

Using a pool tester:

1. Locate a spot in the pool as far away from return jets and the skimmer as possible.
2. Hold the pool tester upside down, up to your elbow deep underwater.
3. Turn the pool tester over and remove it from the water again.
4. Add the appropriate reagent tablets.
5. Seal openings with a thumb and shake the container for a few times.
6. Compare the discolorations of the samples with the respective scales.

Pool testers are used to record the two most important values (pH and free chlorine). These are important for regular pool chemistry analysis. Deeper investigations for specific pool problems are not possible with a pool tester.

Professional testing

When starting the pool after the winter and in case of major problems with the pool chemistry, we advise a professional analysis of the pool water. The experts (for example, from pool specialty stores) record the water quality better than would be possible with home tests.

The professionals will then also give you tips with specific suggestions for dosing the necessary chemicals.

Take a water sample:

1. Take an empty, clean water bottle.
2. Find a spot in the pool as far away from return jets and the skimmer as possible.
3. Hold the bottle upside down up to your elbow deep under the water.
4. Wait until no more air bubbles rise.
5. Turn the bottle over and remove it from the water again.

You can now take the filled bottle to an expert and have it examined.

What values do you test the pool water for?

This is a legitimate question. For this reason, we have created a small overview.

pH-value

Most people still know the pH value from school. This value indicates on a scale from 0 to 14 how acidic or basic the water is. On the scale, 7 stands for neutral. Values above 7 are basic, while anything below 7 is acidic.

In a swimming pool, the ideal pH is between 7.2 and 7.6. Acidic water would attack the filtration system and anything else in contact with water, could range unpleasantly and cause irritation to the eyes. More alkaline water would inhibit the action of the disinfectant chlorine and could be the cause of cloudy water.

Therefore, you should regularly measure the pool pH.

Total alkalinity

The value of total alkalinity (also called TA) is important because alkalinity acts as a buffer for the pH and protects it against sudden fluctuations.

For pools, a TA value between 80 and 150 ppm is the target. A higher value can cause turbidity and scale buildup.

Calcium hardness

Calcium hardness refers to how much calcium is present in the water. Pool owners should aim for a value between 200 and 400 ppm. When it comes to calcium, the problem tends to be keeping it low.

If the calcium hardness is too high, cloudy water can result from the calcium scaling. A very low calcium level can lead to corrosion of the metal.

Disinfectants (chlorine or bromine)

In private pools, chlorine (e.g., in the form of chlorine tablets) and bromine are the most common disinfectants. The level of chlorine should be around 3 ppm and bromine between 3 and 5 ppm.

The chlorine is gradually degraded by the sun. Therefore, you need to replenish it regularly. Cyanuric acid can help you stabilize the chlorine level.

Final tips for testing the pool water

• Before using them, check to see if the test strips have a shelf life. If they are already expired, you should replace the test strips.
• Store test strips in a dry, dark and cool place.
• Take water samples from a depth of at least 30 cm, at a location in the pool that is as far away as possible from return nozzles and from skimmers.
• Test strips reach their final coloration only after about 15 seconds. However, do not wait for minutes to match the color with the color scale.
• Several times a year, the pool water should be tested by a professional.
• Do not add chemicals to the pool unless you know the levels of the water.
• Test the water quality at least weekly.
• The sun has an effect on chlorine concentration. If you have problems with chlorine, test the pool water in the morning to get unadulterated numbers.
• After adding chemicals, you must wait until the pump has circulated the water several times and the chemicals are distributed throughout the pool.
• Do not perform another pool water test within at least the next 24 hours.
• The higher temperatures and heavy use during the summer months encourage algae to proliferate in the pool. This causes the pool to turn greenish when the chlorine concentration is too low. For this reason, you should regularly test the pool water in midsummer. We recommend testing the pool water at least once or twice a week.