Cloudy water rarely means something is broken. It usually means one of your numbers has drifted out of range, and the water is showing it before a test does. The trick is knowing which of the three usual causes you are looking at, because the fix is different for each.
The three usual causes
1. pH or total alkalinity out of range
pH is how acidic or basic the water is, and it wants to sit between 7.2 and 7.6. Total alkalinity is the buffer that holds pH steady, and it wants to sit between 80 and 150 ppm. When either drifts, tiny particles that would normally stay dissolved start to fall out of solution, and the water goes milky.
High pH is the most common version of this. It pushes calcium out of the water as a fine haze and, at the same time, weakens your sanitizer. Set alkalinity correctly first, then pH becomes far easier to hold. Our guide to water balance walks through how these two numbers work together.
2. Weak sanitizer
If the sanitizer level is low, the water cannot clear the everyday load of dead bacteria, body oils and fine debris. It does not always go green straight away. Often the first sign is a dull, cloudy look. Sanitizer strength is best read as ORP, and the target is 650 to 750 mV. Below that, the water starts to lose its ability to keep itself clear.
3. Poor filtration
The filter is what physically pulls fine particles out of the water. A clogged or tired filter, or a pump that is not running long enough each day, lets those particles build up until the water looks hazy. This one is mechanical, not chemical, so no amount of dosing will fix it on its own.
How to get back to clear
Work through the causes in order, because they stack:
- Test and correct total alkalinity to 80 to 150 ppm.
- Bring pH into 7.2 to 7.6.
- Check the sanitizer and shock the water if ORP has dropped.
- Clean or rinse the filter, and run the pump long enough to turn the water over.
Give it a few hours of circulation between steps. Cloudy water usually clears within a day once the underlying number is back in range and the filter is doing its job.
Why it keeps happening
Cloudy water comes back because the drift that caused it happens quietly, between the times you test. By hand, most owners check a few times a week and miss everything in between. That is enough time for pH to climb or sanitizer to fade.
E.W.A. reads pH, sanitizer and temperature every ten minutes, so you see a number start to drift on hour one, not when the water has already gone hazy. It names the exact dose to add for your water, so you are not guessing which bottle to reach for or how much. Clear water becomes something you hold, not something you keep rescuing.
When you would rather hold clear water than chase it, get E.W.A. and let it watch the numbers behind the haze.