I'm adding liquid chlorine daily or every other day

[jeston1]

Hello pool experts. I use liquid 12.5 chlorine and seem to have to use it everyday to every other day to get the FC above 0. I live in NW Ohio and the weather is all over the board, with rain, then sun, then cool, then overcast, etc. My pool is 27' AG and about 18,000 gallons. The water is crystal clear.

Latest water sample done this am by pool store was (and I used a gallon of 12.5 Thursday night):

FC=0
Ph=7.4
TA=90
CH=210
CYA=approx. 20.

I know the CYA has to come up some and I would appreciate finding out what kind of stabilizer to use and how much. Any other help would be most appreciated also. Thank you, I know I will get good advice here.

 

[Texas Splash]

Hey Jeston! Well, to get CYA you need some stabilizer. You can pick some up at Wal-Mart or other local stores (Cyanuric Acid). Use the TFP poomath calculator (link below) to determine how much to add for your pool size. Use the sock method to soak it in your water.

However low CYA may not be your only problem if you are losing FC really fast. All our pools require FC everyday, but losing to much is a problem. Suggest you look into performing an overnight FC loss test (OCLT) and/or ensure your CC (Combined Chlorine) level is not more than .5. If either of these prove true, then a SLAM may be in order. If you aren't familiar with these, please see the links below in my signature and they will guide you. Let us know if you have any other questions.

 

[Richard320]

Poolmath says a gallon of 12.5% in 18000 gallons is 6.9 FC. So in two days, figure 3.5 FC loss per day. With low CYA, that's reasonable.

That said, letting the pool routinely run out of chlorine is begging for an algae bloom. I would follow Splash's suggestion above.