Why Do Pools Turn Green in Central Florida?

Two to three days in peak summer. Warm water accelerates algae reproduction, and unstabilized chlorine can be stripped by UV in a matter of hours. A pool that looked fine on Saturday can be visibly cloudy by Tuesday if chlorine hit zero on Sunday.

A service gap. Eight to ten days without a visit in warm water is the most common cause. Low cyanuric acid. Stabilizer shields chlorine from UV; without enough of it, a sunny Longwood afternoon burns off most of the free chlorine in the pool. A clogged filter. Chemicals kill algae but only the filter removes it, so a loaded filter means the water stays green even while the chlorine reading looks fine.

Most residential green pools clear in two to five days. Lightly cloudy water can turn around in a day. A pool that has been green for weeks with heavy debris on the bottom takes longer, because the filter has to be cleaned repeatedly as it loads up with dead algae.

Almost never in Central Florida. The water table here sits high after a wet season, and draining a pool can float the shell out of the ground — an expensive, sometimes unrecoverable failure. Nearly all green pools clear through treatment and filtration instead.

Fixing the cause, not just the symptom. If the filter was the problem, it needs a full teardown cleaning rather than a backwash. If stabilizer was low, it needs to be brought into the 30–50 ppm range. And the pool needs a weekly schedule, because a bloom that came from a service gap will come back from the next one.