Phosphates In Pool: How To Test It

Just like any property, a pool also requires regular maintenance. Without any regular check and treatments, your pool might turn into a dirty cloudy green pond within a week. This nasty transformation comes from the living algae in the water.

The algae grow and multiply as the result of phosphates increase. Hence, it can be concluded that phosphates are the main cause and needed to be controlled. To get to know them better, here is the explanation.

What are phosphates and where are they from?

Scientifically, phosphate is a chemical compound that is emanated from phosphoric acid. In pools, phosphates usually occur from organic sources like fallen leaves, twigs, even human’s scalps, dead skin cells, urine, and sweat.

Moreover, the water itself could bring the phosphates from its natural origins or get contaminated by phosphoric compounds like fertilizers. The phosphates along with nitrates supply more energy to algae. Therefore, many algae outbreak cases in pools are caused by unbalanced chemical compounds especially phosphates.

How to test phosphates level in your pool

After knowing the cause, it is crucial to clean the pool regularly. Besides cleaning, checking the water level and the chemical compounds is also essential including the phosphates. There are several ways and kits/tools in testing the phosphates like sending the water sample to a lab.

Yet, the simplest action is by self-testing using a pool test kit or a tool. There is a tool called a photometer that can instantly measure the phosphates. You just need to put the water and click the analyze button. More details on test kits at

However, a photometer is quite pricey. The cheaper one is a phosphates test kit. There are several brand options that you can choose with the price ranging from $5 to $25. Some use strips and others involve powder. Then, the kits always provide a test tube and the phosphates chart. Here are the steps.

  1. Put the water pool into the test tube until it reaches the fill line level.
  2. If the kit involves powder, pour it into the test tube. However, if the kit provides a strip, bend the strip and place it in the lid.
  3. Close the tube with the lid.
  4. Invert the tube five times or shake it gently for about thirty seconds until the water turns blue.
  5. Open the lid and place the tube on the white box next to the chart.
  6. With one open eye, observe which color in the chart is similar to the water in the tube.

The color starts from the lightest color that is white to the darkest blue. As it goes dark, the phosphate level is increasing following the color. The pool phosphate kits usually apply a ppm (parts per million) scale.

The cleanest one or white starts at 0 ppm, while the darkest one usually contains 500 ppm or more. Many experts say that the normal level for phosphates is between 100 to 150 ppm. Once the phosphates reach a high number, apply the phosphates remover like lanthanum and clean the pool. Check or change the water filter as the water itself can carry phosphates.