Clearing Up Green Pools

In the summertime, green pools are extremely common. You can find them in vacant homes, residential swimming pools, commercial swimming pools, or in any pool that isn’t regularly maintained. There are many factors that go into why green pools occur and we hope this blog post helps to explain why. Typically, you will see a direct correlation to green algae-filled pools with a lack of chlorine or poor circulation. Whenever you have warm water, algae loves to grow and if you don’t have the proper amount of chlorine in the water, algae will grow rapidly! The same goes for filtration, if you’re not filtering your swimming pool long enough your chances for algae growth increase exponentially. With that said, we also want to focus on a couple of other reasons why your swimming pool can be taken over by algae. The following are the most common:

  • High phosphates
  • High Cyanuric Acid (CYA)

When it comes to water chemistry, it needs to be more comprehensive than just checking chlorine and pH. One additional thing that should be tested for is phosphates which come from vegetation, soils, and fertilizers which is a food for algae. When phosphate levels increase in the swimming pool they must be removed because no matter how much chlorine you use, algae will still spread. Typically, with high phosphates, you will need to purchase a phosphate remover if all your other chemistry levels are within normal ranges and you have chlorine readings. The other major factor could be high CYA levels. CYA helps reduce chlorine loss by protecting the free chlorine in the pool from the sun’s ultraviolet rays, reducing the amount of chlorine needed to maintain proper sanitizer levels. When these levels get too high (typically over 100 ppm), it lessens the effectiveness of chlorine to act as a disinfectant.  Higher levels will bind with the chlorine, making it slower acting to kill bacteria and micro-organisms, and prevent algae from growing! This typically occurs because chlorine tabs have stabilizers in them. Please keep in mind, if your CYA levels are high you will need to substantially increase your Free Chlorine (FC) levels to combat it.

How To Treat Algae

When you’ve determined where the growth is coming from, Weber Pools recommends the following steps to help remove the algae:

  • Identify the type of algae
  • Check chlorine, pH and phosphate levels
  • Check all pool equipment for leaks
  • Check filtration equipment for tears in the filter grids or old sand
  • Check run times for your filter equipment which should be a minimum of 10 hours during the summer
  • Brush, brush, and brush more!

If any of the above is the issue, the addition of more chlorine or increasing your filter run times should help. If you’re dealing with high CYA levels then a water change is necessary. In summary, green pools occur because of a lack of chlorine or poor circulation. To combat the issue, remember to raise your FC levels and filter your swimming pool until it is blue and clear.

Remember If you keep your pool in good shape, you will not only avoid the hassle of having to use various additional chemicals in the swimming pool but also dealing with the unnecessary algae bloom in your swimming pool!