Pool got cloudy out of nowhere - not sure why


Well-known member
May 24, 2018
NB, Canada
Hi all,

Opened to a crystal clear pool this year. Out of nowhere it got cloudy over last few days.

Current testing:

FC 5
CC 0 (does not turn pink at all)
pH 7.2 (threw in 1.5 pounds of borax after the test, should be close to 7.4 now)
TA 80
CH 300
CYA 60
Salut 1600
Borates 20
Temp 86 F

I did 4 different things around the time it got cloudy:

1) Turned heat pump on (went from 72F to 86F in 2 days)
2) Added 60 lbs of salt since I switched from using bleach to SWG since water now warm enough)
3) Added 1 lb of baking soda to get TA up to 70-80 (aiming for CSI over -0.3)
4) Added 2 lbs of dry stabilizer to get CYA closer to my target of 75... currently testing at 60-ish so may add more soon

I noticed a large drop in pH around the same time the pool went cloudy (went from a stable 7.4 down to 7.0 overnight).

I did do a SLAM when I opened, only took a few hours as I passed OCLT/clarity/CC conditions the first night.

It's been a few days and still cloudy. I can see the bottom easily but has like a milky/cloudy look to it. Not as sharp, bright and shiny as it was last week.

EDIT: Filter was cleaned at first sign of cloudiness (it was not very dirty at all), no change. Pump runs 18 hours a day so do not believe it to be filtration related but could be wrong.

Thanks for your help!



Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
The baking soda can cause cloudy water when the right level of pH, TA, and CH are there. Though your pH going down can only happen by adding something acidic. Baking soda is not acidic.

Otherwise, I suspect your 'SLAM' of a few hours did not work. I would suggest going back to the SLAM Process and following it for a few days and then do the Overnight Chlorine Loss Test


Well-known member
May 24, 2018
NB, Canada
Thanks guys... forgot that CYA reduces pH - will remember next time :)

Pool cleared up on its own in a few days. Don't know what it was but assuming it was related to baking soda. Thanks again