Apr 22, 2019

Importance of Monitoring Swimming Pool Chemical Levels

Importance of Monitoring Swimming Pool Chemical Levels

There’s a lot more jumping, diving, floating and splashing in your swimming pool during the warmer months.  Keeping up with pool maintenance is important year-round to ensure a healthy swimming pool. One of the most important elements is the pool chemical levels. It’s easy to overlook or ignore them, but even easier to maintain! This will save you time and money in the long run.


Why are pool chemical levels so important?

The chemicals you put in your swimming pool help balance the water, making it safe to swim in. The right balance of these chemicals keeps your pool clean, and protects the pool finish from discoloration, as well. Most likely, you won’t be changing out the pool water for several years and you’ll have stagnate periods where it’s not being used.  A good filtration system and balance of chemicals will help your pool stay healthy, even when you aren’t using it every day.

How often should I test my pool?

These simple tasks should be performed every week during the seasons when the pool is being used. Testing your water regularly is fundamental to a healthy pool.  You’ll also want to test the pool chemical levels before and after extreme weather. When a rainstorm hits, it causes the water to evaporate, throwing off the pH and chemical levels. The more you test your water, the healthier it can be.

Here are some general guidelines for testing specific pool chemical levels:

  • Chlorine: Minimum once a week
  • pH: Test when you check your Chlorine levels
  • Total Alkalinity: Once per week.  Alkalinity changes the stability of your pH levels.
  • Calcium Hardness: Once per month. These levels will fluctuate depending on weather and added chemicals.
  • Dissolved Solids:  Once per month. If the level gets too high, it directly affects the other chemicals.
  • Salt: Once per month. This is tied to your chlorination system.
  • Metals: Every 3 months. Metals like Manganese, Iron and Copper need to be removed if detected.

What happens if I ignore the pool chemical levels?

Ignoring the pool chemical levels can be a costly mistake.  An abundance of the wrong chemicals or elements could damage your pool’s features, materials and even the equipment in and around it. Most importantly, if you aren’t testing the water, you don’t know if the water is a safe swimming environment!  Proper and routine pool chemical levels testing will prevent you from damaging your pool finish, pool equipment and keep you and your family swimming in healthy, sanitary water.

How do I test my pool chemical levels?

There are four basic ways to test your pool water. Test strips are the easiest and quickest choice. You could also use a liquid test kit, which will give you more detail than strips. A digital testing kit is like an advanced version of the liquid kit. Or, you can take a sample to your local pool store and ask them to test it.

Get a sample of the pool water.  The best place to grab that sample is from the middle of your pool, away from skimmers and jets.  Use a clean cup or bottle to collect your sample. Hold it upside down (opening facing down) and insert it about elbow-deep into the water.  Turn it right side up before bringing it to the top of the water and pulling it out.  This gives you the cleanest possible sample.

There are recommended levels for some of the tests you, or your pool supply store will perform:

  • pH:7.2 – 7.8
  • Chlorine:1.0 – 2.0 ppm
  • Total Alkalinity:80 – 120 ppm
  • Calcium Hardness:200 – 400 ppm
  • Cyanuric Acid:20 – 50 ppm
  • Total Dissolved Solids:below 5000 ppm

Test Strips 

Test strips are inexpensive and an easy option for pool owners.  The strips you’ll use are not complicated. They check for the main components of pool water: pH, Chlorine, and alkalinity.  You can also get strips that will test salt, copper and iron, as well.  To use test strips, you’ll simply dip the strip in the sample water quickly. Hold it still in the air for about 20 seconds. Compare the colors on the strip to the guide on the bottle and adjust your pool chemical levels accordingly.  

Liquid Test Kit 

A basic liquid test kit will do just fine for regular maintenance of your pool.  You will need to ensure that it includes phenol red and orthotolidine (OTO) to test pH and chlorine.  To test, collect a sample in the tube provided by the kit. One side will be designated for pH, the other for Chlorine. For the pH side, add the suggested number of drops of phenol red to the water. For Chlorine testing, add the drops of OTO to the water. Hold the tube up to a white or neutral background (like a sheet of paper) and compare the colors of the water to the scales on the tube.  If the water is more red in color, it indicates high pH, and yellow will show higher Chlorine levels.

Digital Testing Kit

The digital reader will eyeball the color scales for you with a digital testing kit. It’s similar to the liquid kit but does more work for you and tests for more chemicals. It will test total chlorine, bromine, pH, alkalinity, calcium hardness, and cyanuric acid.

Keep in mind that as you adjust the water chemistry, as recommended by the testing kits, the other levels are affected. This could mean that once you adjust one chemical, it directly impacts another – causing you to go in circles. Follow this order for testing:

  • Total alkalinity
  • pH
  • Calcium hardness
  • Cyanuric acid
  • Chlorine

Testing calcium hardness:  Hard and soft water is determined by the levels of calcium and magnesium in it. Buildup can seriously damage your pool filter and pump and cause cloudy water, an ineffective heater and damage pool surfaces. Total hardness should be tested with a professional-grade water testing kit. 

Don’t just get that swimming pool ready for cannonballs and floaties, keep it ready. Ensure that your pool chemical levels are healthy, at least once a week with simple and quick tests. It will protect your pool from future damages and keep the water safe for swimming.

You may also like: Swimming Pool DIY Repairs