Green pool water: what to do first

Step-by-step English guide for green pool water, algae, pH, chlorine, filtration and when not to swim.

Do this first

Close the pool, measure, clean the filter path and brush surfaces before heavy dosing. If the tint appeared after chlorine and well water, metals may be involved.

First decision: close the pool

Do not swim until the water is clear, the bottom is visible and measured values are back in a safe range. Green water can be algae, weak circulation, low sanitizer or metals.

Clean before dosing

Remove debris, empty baskets, clean or backwash the filter and brush walls, steps and corners. Chemicals work poorly when circulation and mechanical cleaning are ignored.

Measure and correct in order

Measure pH and sanitizer first. Correct pH before shock or heavy treatment, then dose only from the product label and measured water volume.

Filter longer and re-check

Run filtration longer than normal, clean the filter again and vacuum dead algae or fine sediment. If water does not improve, check flow, filter media and stabilizer level.