Green water

Algae do not cause disease, but their presence is not inviting to swimmers. Let's fix it together!

<strong>Green</strong> water

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The Problem

Algae in a pool can cause cloudy water, slippery pool surfaces on steps and ladders, pH rise, filter blockage and excessive chemical consumption. Algae can occur due to poor circulation, poor filtration, improper chemical maintenance, or poor housekeeping and environment.

- Green Algae - Tend to be free floating, making the water cloudy with a pea-green color.

- Mustard Algae - Cling to walls, leaving the water clear unless they are physically disturbed. When brushed, mustard algae appears to be a fine brown powder.

- Black Algae - Clings to walls and very difficult to brush.

Recommended solutions

1 Adjust the pH into the range of 7.2-7.4 using HTH™ pH up or HTH™ pH Down. Wait at least one hour.

2 Shock treat the pool with an HTH™ shock product.

3 Brush pool walls thoroughly with an 18" curved wall brush.

4 Run filter for at least 24 hours until water clears.

5 Vacuum the pool.

6 Backwash or clean the filter as appropriate.

7 Add an HTH™ algaecide.

Preventative maintenance

Maintain pH levels between 7.2 - 7.8. Shock treat the pool weekly. Use an HTH™ algaecide weekly.

As always, we’re here to help. If you have questions, contact our help line at 1-866-HTH-POOL or talk to our experts with our live chat!


Please read the following important reminders before adding pool chemicals to water:

• NEVER mix products together or dissolve before use.

• ONLY enter pool when FAC levels are below 4 ppm to prevent risk of bodily harm.