Cloudy after rainfall

[Fibtje]

Above ground soft lined 18ft round pool with sand filter. We had a large rainstorm this week and I can’t get the pool clear and there has been foam on the top. Current levels are
FCI- 10 (I just put in a bunch more shock so I expected this to be high right now)
Alk: 80
PH: 6.2
Th: 450
And the floating dispenser is half full with stabilizer. I put two packets of shock in yesterday but the FC was back to zero a short time after.

[Denniswiseman]

Your pH is way to low and is acidic
Let's have your numbers most important is CYA. Go to a pool store if you can't
FC:
TC:
pH:
TA:
CH:
CYA:
The floating dispenser contains chlorine and CYA
Excessive CYA renders your chlorine ineffective and you have to use more to get the same sanitation
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm
To reduce your CYA you have to do a partial drain and refill
Continous use of Trichlor/Dichlor will raise your CYA which means you have to raise your chlorine level as well