Why Is My Pool Green and How Do I Clear It?

Quick answer: Green pool water is algae, usually caused by low chlorine. Fix pH, brush, shock per the label, run the pump around the clock, and clean the filter until the water is clear and chlorine holds overnight.

Common causes

• Low free chlorine
• High pH, which weakens chlorine
• Poor circulation or a dirty filter
• Heat, heavy rain, or heavy use

What to do

• Test the water and bring pH to about 7.2 to 7.4
• Brush every surface, including steps and corners
• Shock as the product label directs and keep the pump running
• Clean or backwash the filter often during treatment
• Retest and repeat until the water is clear and chlorine holds overnight

When to call a pro

Call a pro if the pool is very dark, the algae keeps returning, or you cannot keep chlorine steady.