New liner - Water good for 6 weeks - Went cloudy over weekend


Jun 27, 2008
Hi all, Please advise

Should I "SLAM" the pool with Liquid or use none CL oxidizer (Potassium monopersulphate) which I bought? I dont want to bleach a new $5000 liner. I called the Lathan liners and asked how high can the CL go to below bleaching. They wouldn't answer the question.

New liner installed July 14th, New water from town supply. Water chemistry was ok until this weekend. Im using Chlorine feeder with stablized pucks but I think it had an air lock or is clogged and CL dropped too low. Had heavy rains. Went away for the weekend and came back home and water is cloudy (whiteish not green) No algee visible.

Checked FC and was zero with test strips. Last night I shocked with 4 liters liquid CL (10% to12%) waited 30 mins and retested still 0 FC. Added another 3-4 liters (what I had left). Checked test strip again 15 mins later 0 FC but 5CC

Today it tested water and had pool store test as well. My tests were with with a brand new Taylor K1005 and DPD FAS kit
Outdoor vinyl pool 77000 liters (not salt) - No heat added, No cover, 75% Sun exposure
Pool has 500ml of 60 % poly-quat added July 21st

Pool store tests with Waterlink spin touch machine
FC - 0.36 - (My test FAS shows FC 1.1)
CC - 2.45 - (My test FAS shows CC 2.8)
PH - 7.7 - (My test 7.5 to 7.7)
HD - 102ppm
Alka - 96 (My test 100-110)
CYA - 44 - (My test strips show 30 - 50)
Copper - 0
Iron - 0.1
Phos - 37ppm
Temp - 78F

Update @ 10:45PM retested and decided SLAM. Added 7700ml CL (10-12% liquid pool store stuff)
FC 1.8 (FAS) - Start
CC 2.0 - Start

FC 4.5 (FAS)
CC 0.5 or less (10ml sample had hint of pink before starting adding #R003. Added 1 drop and started stirrer. Made it clear (opposite effect) but good regardless)
Still cloudy but see in morning....

7 days later... for those who care...
Pools FC was held at 2 to 4ppm each dayand tests showed 0 CC all days via DPD tests. Added Liquid as needed at night
Day 2 added 1/2 cup PE powered to sand filter for 1 PSI increase
Cloudiness cleared up 100% buy morning of day 3.

Pool is normal now.
Last edited:


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
If your CYA is 50 then your SLAM level should be 20. See FC/CYA Chart. So I don’t know what you are doing.

You need to follow the SLAM Process step by step with no shortcuts.

Keeping the FC within the levels for your CYA will not bleach the liner. But we don’t trust pool store tests or strips. So you need to get your own test kit to accurately measure CYA and all other water chemicals.
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