Cloudy water after about a month of good swimming conditions

[DossC04]

I am interested in some advice on how to get my pool back to crystal clear because over the past couple days it has gotten cloudy. When I first noticed, I added chlorine and today tested to find the following levels:

FC - 9
CC - 0
TA - 80-90
CYA - 80

In looking at the TFTestKit suggested levels, I know that my CYA is high because of an improper addition of CYA at the opening of my pool, but from advice from some members here, it sounds like that is ok. I also notice that my alkalinity is a little low and was wondering if that could be what is causing the cloudiness or if it might be something else.

I think it is included in my signature, but I have an above ground ~30' round ~21000 gallons with sand filter.

 

[Texas Splash]

I suspect the issue is algae or the presence of organic material trying to form. The TA shouldn't have anything to do with it. While your FC is indeed on the low end of the recommended range, all you can do is reflect back to see if the FC dipped too low at some point leading to the cloudiness. But cloudy is better than green, and the sooner you increase the FC to SLAM level the better. My main concern would be the well water (iron), because when you push the FC up to the SLAM level of 31, it may turn that iron brown or some other color for a while. But regardless, when a pool has algae, a SLAM is the cure.

If you have any reservations about algae and doing a SLAM, at least consider an overnight (OCLT) tonight to see if you lose more than 1 ppm by morning. That should be a good indicator. Even if you don't SLAM starting tonight, I would increase the FC about halfway - say to about 15-16 just to help the chlorine get the upper hand. Hope that helps.

PS ~ Don't forget to lower pH to about 7.2 before doing a SLAM if/when you start.