Why Florida Pools Turn Green in the Summer (and How to Fix It)

You look out on Monday and the pool is crystal clear. By Thursday, after a couple of afternoon storms, it's cloudy and turning green. That's algae, and in a Florida summer it can take over in just a few days.

What turns a pool green

Rain dilutes your chlorine. A heavy afternoon storm adds a lot of fresh water, and your chlorine level drops right when you need it most.

Storms wash in algae food. Leaves, pollen and grass clippings blow in and use up chlorine as they break down. Runoff can also carry phosphates from fertilizer, which algae feed on.

Sun burns through chlorine. Sunlight breaks chlorine down quickly. That's why outdoor pools use a stabilizer, but even with it, a hot, sunny week takes a toll.

Heat speeds everything up. Algae grows fastest in warm water, and our pools stay warm from May to October.

Poor circulation leaves dead spots. A clogged filter, full baskets, or a pump that isn't running long enough leaves corners where algae gets a foothold.

For reference, the CDC recommends keeping a home pool at a pH between 7.0 and 7.8. Chlorine should be at least 1 ppm, or at least 2 ppm if the pool uses stabilizer. After a big storm, a pool can drop below that fast.

How we get it back to clear (green-to-clean)

Every green pool is different, but recovery usually looks like this:

1. Clear the debris and empty the baskets so water can flow.
2. Test the water and balance the chemistry so the chlorine can do its job.
3. Shock the pool with a heavy dose of chlorine to kill the algae, and add an algaecide to help speed up the process.
4. Brush everything: walls, steps and floor, to break up algae so it can be filtered out.
5. Run and clean the filter. Dead algae ends up in the filter, and it may need cleaning more than once.
6. Vacuum and re-test until the water is clear and stays balanced.

A lightly green pool can clear in a day or two. A swamp that's been sitting for weeks can take several visits.

Preventing it

• Test your water after heavy rain, not just on schedule
• Keep baskets empty and the filter clean
• Run your pump long enough to turn over the water every day
• Trim plants that drop leaves into the pool
• Consider an automatic pool cleaner. It picks up leaves and dirt between visits, so less debris sits in the water using up your chlorine, and the pool is easier to keep clean

Or let us handle it. With regular cleaning service, we test and balance your water every visit and send you a photo report. That way you'll see a problem coming before it turns green.

Pool already green? Call (352) 773-0088 or request a free quote. I handle green-to-clean recoveries across Spring Hill, Brooksville, Weeki Wachee and Hernando County.