Why Is My Pool Cloudy?

Published August 20, 2026

Cloudy water is one of the more common calls we get, and it's usually not as bad as it looks. Hazy or milky water is different from green water: green means algae has already taken hold, while cloudy usually means something fine and suspended is in the water and nothing is pulling it out fast enough. There are four likely causes, and they're worth ruling out in order.

Start With the Filter

The most common reason a pool goes cloudy is that filtration isn't keeping up. Cloudiness is often just fine particulate (dust, pollen, dead organic material) that the filter hasn't caught yet. If the pump isn't running long enough each day, the water simply isn't making enough passes through the filter to clear it.

Run time is the first thing to check. In South Florida summer, a pool generally needs more hours per day than it does in winter, and a schedule set months ago may be short now. After that, look at the filter itself. A cartridge caked with debris filters less, not more, and a sand or DE filter that's overdue for a backwash is pushing water around the dirt instead of through it. If the pressure gauge is running high, that's your signal.

Sometimes it isn't maintenance at all. A torn cartridge, a cracked lateral, or a bad o-ring lets water bypass the media entirely, and no amount of run time will clear the pool. That's the kind of thing our minor repairs work covers, and it's worth ruling out before you start pouring chemicals in.

Chlorine That Can't Keep Up

The second cause is sanitizer. Chlorine's job is to oxidize the fine organic material that ends up in every pool: sunscreen, body oils, sweat, pollen, dust. When free chlorine runs low, that material doesn't get broken down. It stays suspended, and suspended material is what you're seeing when the water looks milky.

This is where a fixed weekly dose falls short. Bather load, heat, and rain all change how fast chlorine gets consumed, and they change week to week. We wrote about this after a recent stretch of record heat. A pool that held fine on Tuesday can be running short by Friday because the conditions moved underneath it. We don't guess at the number. Live digital readings, your pool's size, the week's weather, and how your water has shifted since the last visit all feed our dosing system, so the dose matches the week you're actually in.

pH and Alkalinity Out of Range

This one gets misdiagnosed a lot, because the fix isn't chlorine. When pH or total alkalinity climb too high, dissolved minerals in the water (calcium in particular) stop staying fully dissolved and start coming out of solution as fine suspended particles. The result is that same milky look, but the mechanism is entirely different. You can add chlorine all week and it won't clear. The balance itself has to come back into range first, and then the filter can do its part.

Chloramines: Chlorine That's Already Spent

If the water smells strongly of chlorine but doesn't act like it, you're likely dealing with chloramines, also called combined chlorine. That's chlorine that has already reacted with contaminants in the water and is now inactive. It still shows up on a total chlorine test, but it isn't sanitizing anything, and that sharp pool smell people associate with clean water is actually the smell of chlorine that's done working.

Adding more regular chlorine doesn't solve this. It takes a shock treatment at a high enough level to break those bonds apart and restore real sanitizing power. Once that happens, free chlorine can go back to doing its job.

Cloudy Is Often the Step Before Green

Cloudy water with low chlorine is the exact setup an algae bloom needs: warm water, weak sanitizer, plenty of organic material. That's why it's worth addressing quickly rather than watching it for a week. Caught early, it's a chemistry and filtration correction. Caught late, it's a green-to-clean job, which is a different and longer process.

Most cloudy water is fixable if you get to it early. The reason it usually isn't caught early is that testing happens on a fixed routine instead of responding to what the water is actually doing that week. If you'd rather not track it yourself, that's what weekly maintenance is for: readings, dosing, and an equipment check every visit, with a photo and service report so you can see the pool's condition without standing over it. We work across Coral Springs and Tamarac, and we're happy to take a look at what's going on with yours.