CYA jumped to 100 with pool-math calculation

southflorida427

Well-known member
Apr 27, 2017
97
Miami FL
Scratching my head, usually the math works great.

I added 3lbs dry CYA for my 13K gallon pool that measured 40ish CYA to try to take it to SWG recommended level of 70.

I also added salt, calcium, acid, recently. Reasons I’m our of wack: dear kids left the water hose Inside pool overnight and I found myself with a diluted infinity patio/pool in the morning...

Today tested with both taylor and pentair (this one new, arrived today) test kits and I’m around 100.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
36,202
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Well, either the first CYA test was incorrect, you added more than 3 lbs of CYA, your pool volume is much less than you thought, or the last CYA test is incorrect. Or the pool is just not mixed up well. Did you run the pump a full 24 hours after the CYA was dissolved completely?
 
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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
23,763
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
3lbs of stabilizer will raise your CYA by 28. It sounds like your CYA started about 60 ish.
 
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southflorida427

Well-known member
Apr 27, 2017
97
Miami FL
Yup, it’s been running for 24 hours already. I do notice the filter went up in pressure a bit.

I think today’ test are OK, I bought 5 lbs acid and still have 2lbs in the bag. Pool size I’ve been using for years to calcule chemical additions.

The only part I guess I cannot corroborate is the 40ish test.
Next time I’ll add in smaller batches.

Anything else that could be going on?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,932
San Dimas, CA (LA County)
Unless you have algae, or suspect it, you can just run a higher FC.

At least until you figure this out. Maybe consider CYA to be 100 for now, run the higher FC level for a few days, and then recheck it and move forward from there. I could understand wanting to postpone water replacement until the next billing cycle since you've already added a whole bunch.

My guess is that the water wasn't mixed well enough before you ran the first test.
 
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