Why Is My Pool Cloudy? | Poole's Pools

Cloudy water is one of the most common calls we get, especially as the weather warms up in spring. It is rarely one single thing. Most of the time it is a mix of water balance and filtration, and testing tells you which.

The usual causes

Low chlorine. When chlorine runs low, tiny particles and early algae build up and the water loses its sparkle.
High pH or alkalinity. When pH climbs, chlorine works poorly and calcium can come out of the water as a fine haze.
High calcium hardness. Common in older pools and pools topped up often, and it shows as a milky look.
A filter that is not keeping up. A dirty filter, worn media or short run times leave fine particles in the water.
A sudden load. Heavy rain, a hot spell or a pool full of swimmers can use up chlorine faster than the pool can make it.

What to do

Test the water first. Guessing usually means adding the wrong chemical.
Balance the pH before anything else. A pH of around 7.2 to 7.6 lets chlorine do its job.
Bring the chlorine up and keep it there.
Clean the filter, and run the pump for longer until the water clears.
Brush the walls and floor so the filter can catch what has settled.

Most cloudy pools clear within a day or two once the balance and filtration are right. If yours does not, the filter media may be worn out, or something like phosphate or very high stabiliser may be the cause.

Why we test so much

We test every pool on every visit with a LaMotte Spin Touch, which runs 10 tests from one sample. It picks up the things a test strip misses, such as calcium, stabiliser and phosphate creeping up, so we can fix the cause rather than just the cloudiness.

Still cloudy?

Get in touch and we will test the water, check the filter and tell you what is going on.