cyuranic acid level dropped over winter

jlbaker999

Member
Jun 9, 2018
6
lubbock,tx
I have had high CYA levels and have gone to liquid bleach. In the mean time I was going to get the CYA levels corrected when I started up the pool this year. I have the suggested Taylor test kit (FAS-DPD chlorine with R-0013 CYA reagent)and thought I would check the CYA levels to see where I am. CYA doesn't even show up at all. Last year it was running 80 - 90 or so. BTW, Walmart has 10% Pool Chlorinating Liquid (bleach) for $3.24 a gallon.
So, does CYA go away over the course of 5 months ???
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,470
Laughlin, NV
Welcome to the forum!

That severe a drop can be concerning.

I suggest you do the following prior to adding any CYA.

To check and defeat ammonia, if necessary, is to raise your FC in the water using enough liquid chlorine to get to 10 ppm using PoolMath. Circulate the pool for 15 minutes. Test FC. If at 5 or below, add LC to get to 10 using LC, circulate for 15 minutes, repeat until your FC is above 5 ppm after the 15 minute circulation.

If you pass the above, then add sufficient CYA to reach 40 ppm using the sock method.

I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
11,726
Houston, Texas
Hi, welcome to TFP! Did you allow the water to circulate about 30 minutes before you took your first test? Did you have a lot of rain over the winter? How does your water look? If you did circulate the water before the CYA test then follow the protocol Marty gave you. It is important that you are able to hold a chlorine level before adding CYA.
 

jlbaker999

Member
Jun 9, 2018
6
lubbock,tx
Well, no I didn't circulate the water at all. The water level is low (drops over winter) and I haven't even taken the cover off. Probly I"m measuring the water at the top. I"ll fill and circulate and go from there.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,470
Laughlin, NV
Being in the climate you are I did not even consider the pool was closed for the winter.

Do fill the pool and do a good brush and circulation and then take your sample for testing.

Take care.
 

Arizonarob

Gold Supporter
Silver Supporter
TFP Guide
Mar 25, 2018
2,879
Chandler Arizona
Hi JL, :wave:

A word of caution when buying liquid chlorine from big box stores. Learn to read the date code on chlorine bottles, you don’t want to use anything past 3 months since made. I have seen Walmart start pulling out overstock from last season, that is old. The 2 packs they are putting out have a date code of 18 244. :oops:
I’ve been buying the single gallon jugs, as they are the freshest, until they start getting in the 2 pack of new product.

In the photo below, the first 5 digits are the year and date it was made. So the first two are the year, 18, then the last 3 are the day of the year, 346. So this batch was made Dec 12th, 2018.
You will start to see fresh batches with 19 022 etc, as an example coming up. :cheers:
07576769-CE5C-475D-90F9-5764E92348F0.jpeg
 
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kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
41,589
Tallahassee, FL
I will tell you I lose most of my CYA over the winter due to large amounts of rain. Rain water going in=pool water coming out=lose of CYA. Here is hoping that is what is going on with yours. Marty has you heading in the right direction to see what is what just in case.

Kim:kim:
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
32,859
Sebring, Florida
Several things can contribute to the apparent loss of CYA over the winter. The best approach would most likely to refill your pool to it's operational level, run the pump as you are filling and then stop and take a COMPLETE set of test results. Go forward from there.
 

AUSpool

Bronze Supporter
LifeTime Supporter
TFP Guide
Sep 23, 2015
669
Brisbane, Australia.
I don’t know if its a myth but I have read about low a temperature interference on the CYA test that gives a false low reading. There is nothing about a low temperature interference in the extended test instructions and I haven’t been able to find anything on the Taylor site.
 

hopkiba

Active member
Apr 7, 2011
27
Cleveland, TN
I had a similar experience. I keep my pool open and there was record rain this winter. Both my CYA and salt dropped 50%. I was doubting my tests but it the results seem to confirm each other.