Mysterious white flakes showing up only at night?

[syedsam]

Okay this is going to sound weird, but maybe someone’s seen this before… During the day my pool looks crystal clear. But every single morning when I pull the cover off, the floor has these little white flaky things scattered around, like someone sprinkled crushed-up eggshells overnight. By midday, they’re gone again (I assume they get sucked into the filter or dissolve?).


I thought it was calcium scale at first, but my calcium hardness is actually on the low side (190 ppm). Chlorine is steady, pH normal. The oddest part is it only appears overnight never while we’re swimming or when the pump is running. Almost like something is “forming” in the still water.


Anybody ever deal with this? Could it be some reaction with the cover on, or maybe my heater spitting out scale bits when it cools? I’m half-joking that my pool is growing dandruff at night.

 

[Lily Allen]

I’ve seen that too! Turns out it could be a reaction between the water and the cooler temperature from the cover or heater. If the filter hasn’t been working at its best, sometimes mineral residue in the water can settle. Maybe try checking the heating system and filter thoroughly.

 

[Ella Robinson]

I’ve seen the same thing it’s usually mineral flakes that form when the water cools under the cover. Try running the pump for 1–2 hours at night, clean/check the filter and heater, and if needed add a little scale inhibitor. That usually fixes it.

 

[Grace Hall]

Sounds like mineral flakes forming when the water cools at night. I’d run the pump 1–2 hours at night, clean the filter/heater, and if it still shows up add a little anti-scale product. That usually does it.

 

[Isabella Morales]

I’ve seen something similar usually it’s mineral flakes forming when the water cools down at night. I started running the pump for an hour or two before bed and cleaned the filter/heater, and the flakes stopped showing up.