Cloudy or milky pool water: causes and fixes

Dull, white or milky pool water: the most common causes (high pH, filter, low chlorine) and how to fix them.

2 min read

Cloudy water is water with particles too fine for the filter to catch. Most of the time the cause is one of these:

• High pH (above 7.8): the most common cause.
• Filter not running long enough, or dirty sand or cartridge.
• Low chlorine, with algae starting (not green yet).
• Lots of swimmers, sunscreen and dust.

What to do, in order

1. Test the pH. If it's high, lower it with pH reducer and wait 4 to 6 hours.

2. Check the chlorine and give the pool an extra clean if it's below 1 ppm.

3. Run the filter for 8 hours straight and backwash if the pressure is high.

4. If it hasn't cleared in 24 hours, a clarifier helps clump the particles so the filter can catch them.

Don't use a clarifier and a flocculant at the same time, and never in the same bucket as chlorine.