Loss of CYA and CH

bankOman

Well-known member
Oct 21, 2015
191
North Richland Hills, Texas
Hello all!

Over the winter I must have lost some CYA. Last summer I had a 70-80 CYA and now I tested and I only have 20-25. During the winter I typically only tested the FC/CC and PH. Which were always in line until last week. Last week my FC were at 1 (previously always at 4-5) w/ SWG running at 10%. So I ran the boost on the SWG and added some bleach to get it up to recommend levels rather quickly. This is when I tested CYA to notice the big drop. So I'm now running the SWG at 50% and it is keeping the FC in recommend levels. So I believe I just need to increase my CYA to get it to hold the chlorine so I'll be able to turn down my SWG % so it's not working so hard. I also had a drop in CH, previously was at 350-400, now I'm at 275. What would cause the drop in CH? Lots of rain? Is this bad for a plaster pool? Last question, I also for the first time have more than .5 CC it was at 1 today. Was this maybe due to adding the bleach for the first time last week? I'm not sure...Any help or guidance would be appreciated!

FC 4.5
CC 1 (always .5 or lower before today)
PH 7.8 (just added 34oz MA)
TA 90 (increased from 80 last week, hoping with dropping PH back down this will fall back in line)
CH 275
CYA 20-25 (do I just add liquid CYA, is there a brand from a pool store that's recommended...I'm fine w/ paying more for liquid for ease and time sake)

*Weather related note if it matters we had about an inch of rain the day before yesterday
*Water observations: Water looks crystal clear
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
9,417
Evans, Georgia
Hey there BankOman :)

Sorry to hear about the pool woes.

Any chance you have had a leak? If you have an auto filler on your pool you could easily be unaware of a leak until your water bill came, or as you have discovered your chemical levels change. The only thing that gets rid of calcium and cya is water replacement, although sometimes cya degrades over winter but that's usually so minimal it doesn't cause a lot of problems. Or have you had to drain and replace water in the pool for any reason?

It might be time for a bucket test --> Pool School - Leak Detection

Yippee :flower:
 

bankOman

Well-known member
Oct 21, 2015
191
North Richland Hills, Texas
I was thinking that however my water bill hasn't seen any increase. Next week I will do the bucket test to hopefully rule that out. We have some rain coming so not a reliable time to do the bucket test. And no replacement of water other than the normal auto fill.


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YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
9,417
Evans, Georgia
Aha! so you do have an autofill. That's gotta be the explanation (in my mind) and you've got an occult leak someplace I bet.

Go look around your equipment pad and the yard.... notice any wet spots you can't explain? Is there any way to turn the autofill off and give it a few days to watch for a loss?

Yippee :flower:
 

bankOman

Well-known member
Oct 21, 2015
191
North Richland Hills, Texas
Aha! so you do have an autofill. That's gotta be the explanation (in my mind) and you've got an occult leak someplace I bet.

Go look around your equipment pad and the yard.... notice any wet spots you can't explain? Is there any way to turn the autofill off and give it a few days to watch for a loss?

Yippee :flower:
I've checked around the equipment and don't see any water. Hard to notice with the yard since it's all synthetic grass.

I can turn the auto fill off. Next week the weather should be better and no rain so I'll test it all then.

In the meantime will having a lower than recommended CH for a plaster pool have any adverse effects?

With the low CYA assuming I keep running my SWG at a higher % to keep FC up I should be fine in the meantime?

Does my thought process on that sound right?

Thanks for the help!


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duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
31,537
Sebring, Florida
We have some rain coming so not a reliable time to do the bucket test.
The rain doesn't matter. Bucket and pool are affected equally.

CH of 275 is just fine. I would leave it alone as it will tend to rise slowly anyway.

Yeah, you will most surely have to increase your FC % output.