Green Pool Recovery: The Step-by-Step We Use to Clear Algae in 72 Hours

A green pool isn't a chemistry problem. It's a circulation, sanitation, and filtration problem all happening at once. Throwing chlorine at it without fixing the other two is how homeowners burn through hundreds of dollars and still have a swamp.

Here's the recovery sequence we use on every green-pool call across Rockwall County, Collin County, and East Dallas County.

Step 1 — Test and balance pH first

Chlorine is up to 10x more effective at pH 7.2 than at pH 8.2. Bring pH down before you shock or you're throwing money at the water.

Step 2 — Triple-shock with calcium hypocal

Granular cal hypo (not liquid bleach, not dichlor) at 3x the label rate. Broadcast around the perimeter with the pump running. CYA must be under 50 ppm or shock won't break through.

Step 3 — Brush every surface, twice

Algae cell walls protect interior cells. Brushing physically breaks the colony so chlorine can reach what's inside.

Step 4 — Run filter 24/7 for 72 hours

Backwash or rinse every 12 hours. Dead algae becomes filter food. Skipping this step is why pools turn from green to cloudy white and stay there for a week.

The 3 mistakes that wreck recoveries

Mistake 1: Adding algaecide before shock. It binds chlorine and stalls the kill.

Mistake 2: Vacuuming to waste before brushing. You leave the cell walls behind to regrow.

Mistake 3: Stopping at 'blue but cloudy'. That's bacteria, not algae — and it'll go green again in 48 hours without follow-through.