Loss of CYA over Summer

danielduerr

Gold Supporter
Nov 2, 2016
10
Carmel Valley, California
I had 75 ppm of CYA in March and tested it again yesterday to find it was <15 ppm using Taylor K-2006 kit. I am confident in my test ability, but don't normally test CYA due to historical experience that once stable, it doesn't go away without water change. Like the others here, I am confident I do not have a leak or abnormal loss of water. I opened the pool on 4/15 and have kept it at 90 all summer, with one accidental day where my son turned it up to 100 (solar got us to 99 by the time I caught it). So I am thinking it may be heat/temp related as suggested earlier here?
 
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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,396
Laughlin, NV
Welcome to the forum!
CYA does degrade some during the summer months. Mostly due to elevated water temperatures. Splash out, backwashing/filter cleaning, etc, can have an effect. Also, the testing method, at best, is =/- 10 ppm.

Add 20 ppm of CYA granules using the sock method. Once dissolved, test the CYA after 24 hours.

I suggest you read ABC's of Pool Water Chemistry.
 

danielduerr

Gold Supporter
Nov 2, 2016
10
Carmel Valley, California
Thanks @mknauss! I've been following your ABCs since pool construction in 2016 but this is my first post. ;) Love you guys and have turned a number of fellow pool owners on to your fool-proof methods.

We admittedly keep our pool on the warmer side, so it makes sense we'd see an effect here. And agreed on the variance with the test, particularly since I have good eyesight and a little light can have a dramatic effect on the dot. I tested CYA three times yesterday using 3 different reagents in my stockpile just to make sure the result was consistent.

I found the sock/granule method a bit tedious to get to the CYA levels I was after, so I switched to using liquid form stabilizer, specifically the Natural Chemistry product on Amazon.com. I understand either solid or liquid form is the same thing. But do you think there might be a difference in how I dosed the liquid form that might have led to a faster dissipation of the CYA?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,396
Laughlin, NV
I have never used the liquid. I would think it is the same as solid as to resulting CYA levels.

I have heard on this forum that you need to use the entire bottle of liquid when you use it. The particulates settle in the bottle and must be washed out.

I suggest you monitor your CYA each month during swim season. Add via trichlor if you wish. I do that when my CYA falls. Which it does, normally ~10 ppm per month from May to October.
 

Katodude

Silver Supporter
Aug 22, 2017
318
West Palm Beach/Florida
Also the warmer your water the faster CYA will dissolve with the sock method. If you water is 90 or above it will dissolve very quickly in front of a return. I order a box of 25lb of CYA almost yearly from Amazon, best price per lb I can find.