CYA way to high.

May 18, 2016
3
Enterprise,MS
My CYA is currently between 100 and 140. I have the TF 100 test kit and it shows 100 but I did the test with have pool water and half tap water and it read 70, so I multiplied by 2 and got 140. I am currently pumping water out of my pool using waste mode. I was courious of approximately how much I will have to pump out. Any help would be greatly appreciated.
 
:wave: Welcome to TFP!!!

It is linear. Replace 50% of the water, lower the CYA by 50%. Replace 75% of the water, lower the CYA by 75%

BUT ... what is your ground water level? You might not be able to pump out that much at once. You should also leave at least 1 foot of water in the shallow end so the line does not shift.

Are you pumping from an isolated floor drain? Otherwise you will only be able to pump to the bottom of the skimmers.
 
I like easy math - for people like me :) ....so, if your CYA is 140, exchanging 50% should lower CYA to about 70. You could exchange more water to try and get the CYA down to about 50-60, but we always like to caution people about how far to lower water in the pool. You don't want to compromise the structure or have the pool try to "float" if you're in an area with a high water table. Never go below the last step, or lower than about 12 inches. Having said that, the Poolmath calculator (link below) indicates that to go from 140 to 50, you would have to exchange about 64% of your water. Hope that helps. Oh, and welcome to TFP! :wave: Nice to have you with us.
 
Ok thanks guys I have a pretty high water table in my yard. I was planning on pumping down about 12" the first go round checking CYA again and going from there. And then I have to figure out what type of chlorine to use once I get it right. I have been using the Members Mark 3" tablets in my skimmers and I think I had to much in there and if I am correct they have the stabilizer as well and I think that is where my problem came about. I have a friend that said he only uses liquid chlorine but I don't know how much of it to use. I am just learning I guess.
 
If you are doing 1 foot drain and refill at a time, that is likely close to 25%. I would do that 3 times and then retest, you might then need to do it 1 or 2 more times.
 
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