New pool owner - high CYA - trying to hold off drain til Fall

brojackson

New member
Aug 3, 2020
3
San Antonio, TX
Like the title, I'm a new pool owner (~16,000gal, plaster, DE Filter) and have been having issues with CYA. I had it tested at the pool store, and they were telling me it was "120+," and duped me into Bioactive (like I said...new pool owner). I bought the TF100 kit and have been testing -- CYA is still coming back high (140ish) but I haven't done the diluted test, yet, so I don't EXACT, but I know it's quite high.

I know the best way to fix it is with a drain, which I'm fine doing, but I keep reading that you don't want to do it when it's hot. Unfortunately, I'm in SoTX and it was 102 the other day with a heat index of 117. Going off that, I'm probably looking at two months from now. So, I want to manage it until then, if possible (unless you think a drain is fine in the heat).

My main question is, about what am I looking at daily in liquid chlorine to keep it swimmable? I can't wrap my head around the ppm compared to how many gallons that is, and how much I actually need to add. I know it will click for me, but right now it's like I'm trying to pass college algebra again.

Can someone help me out a bit here with this? Happy to give more details - just let me know what would be helpful.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,373
Laughlin, NV
Welcome to the forum!
Do the extended CYA test.
I suspect you can drain it much sooner than you think.
Let us know more about your pool equipment by filling out your signature.
Can you post a full set of test results?
Have you tried the PoolMath app? That will calculate volumes of chemical needed based on your current test results and your goals.
I suggest you read ABC's of Pool Water Chemistry.
 

brojackson

New member
Aug 3, 2020
3
San Antonio, TX
Welcome to the forum!
Do the extended CYA test.
I suspect you can drain it much sooner than you think.
Let us know more about your pool equipment by filling out your signature.
Can you post a full set of test results?
Have you tried the PoolMath app? That will calculate volumes of chemical needed based on your current test results and your goals.
I suggest you read ABC's of Pool Water Chemistry.
Sure thing - just added signature. I'll add more detailed info as I can pull it together.

Just did a test with the TF-100 -- are these numbers helpful?

CYA: ~130 (did diluted test 2x and got about 65 each time)
FC: 0 - 0.5
PH: 8.2
TA: 120

I know everything is a bit wonky - I bought 4 gallons of 31.45% Muriatic, and a PH calculator tells me to add ~27oz.

An FC calculator tells me to add about 2 gallons of 10.5% chlorine/bleach.

My question is, with the CYA high, am I needing to add that much chlorine every day? What's a normal amount to add daily when things are good?

I currently have an in-line chlorinator using the stabilized pucks, which is probably how the CYA got high in the first place, but if I can get everything dialed in, I may just move to liquid and add my own CYA. Just need to get it dialed in first.
 
Last edited:

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,373
Laughlin, NV
To keep the water sanitary, you need to maintain the FC at 7.5% of CYA at the minimum. So that puts your FC at 11 ppm minimum. Issue is your pH test is not valid at a FC above 10 ppm. So the elevated CYA presents a problem.
If you still have tablets you need to discontinue their use.
Adjust the pH now and then add liquid chlorine. Add liquid chlorine every day to keep your FC level above 11 ppm.
 

Yev

Well-known member
Jul 29, 2014
547
Independence, KY
I currently have an in-line chlorinator using the stabilized pucks, which is probably how the CYA got high in the first place, but if I can get everything dialed in, I may just move to liquid and add my own CYA. Just need to get it dialed in first.
Marty said this, but I am going to be more direct.

You have only 2 choices on what to do next with regards to your chlorine.

Option 1 - Stop using chlorine tablets and switch to liquid chlorine. With this method, you will want to get yoru CYA down to around 50-60

Option 2 - Stop using chlorine tablets and install a salt water generator. With this method, you will probably want to get your CYA down to about 80-90

Regardless, I want to make sure a few other things are clear.

Unless you completely replace your water, you do not need to add your own CYA. You want less CYA. Once you get it to a good range, only add it if it drops below the range, you dont need to regularly add it.

You can partially replace somewater right now. The least efficient method, but it will still work during the heat, add water to your pool while operating a submersible pump to drain at the same time. If you replace about 3K or 4K gallons, your CYA will be in a much better place. Or you can drain a 12 to 18 inches (check before you do this to make sure that it is OK to have some of yoru walls out in the air smarter people will weigh in here) and then add water back in to fill. One effective technique is to pump out about an inch of water before you know you are going to get some bigger rain storms. Let the rain replace the drained water.
 

brojackson

New member
Aug 3, 2020
3
San Antonio, TX
Marty said this, but I am going to be more direct.

You have only 2 choices on what to do next with regards to your chlorine.

Option 1 - Stop using chlorine tablets and switch to liquid chlorine. With this method, you will want to get yoru CYA down to around 50-60

Option 2 - Stop using chlorine tablets and install a salt water generator. With this method, you will probably want to get your CYA down to about 80-90

Regardless, I want to make sure a few other things are clear.

Unless you completely replace your water, you do not need to add your own CYA. You want less CYA. Once you get it to a good range, only add it if it drops below the range, you dont need to regularly add it.

You can partially replace somewater right now. The least efficient method, but it will still work during the heat, add water to your pool while operating a submersible pump to drain at the same time. If you replace about 3K or 4K gallons, your CYA will be in a much better place. Or you can drain a 12 to 18 inches (check before you do this to make sure that it is OK to have some of yoru walls out in the air smarter people will weigh in here) and then add water back in to fill. One effective technique is to pump out about an inch of water before you know you are going to get some bigger rain storms. Let the rain replace the drained water.
Yeah, I meant more that I would just stop using stabilized pucks. I won't do a full drain, so I imagine it will still have plenty in there if I do a few partials to get it down to manageable.