Opened pool to Crystal Clear Water... but test shows no CYA after fighting high CYA last pool season

dwhitt

Member
Jun 6, 2019
10
Pasco, WA
So I started trouble free pool last year after buying my home. I fought very high CYA levels from the previous owner, pumping and filling water to lower CYA. Last season I ended with a CYA of 70. Closed the pool and this year opened the pool to crystal clear water and very little clean up. I assume that I need to do a SLAM to start the pool season. However, When I ran a chemical test I got these results?
FC- 2.8
TA-70
Temp-56
PH-7.6
CH-80
CYA-0 ???

Can
anyone help me out on where to start? I would like to open the pool correctly and have the same type of year I had last year after fighting CYA. Please Help?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
31,291
Laughlin, NV
Great. Very low water temperature can effect the CYA test. So be sure the sample is normal room temperature.
You can start dissolving 30 ppm worth of CYA. Once it is fully dissolved, test the CYA again at 24 hours or more.
 

kodiak1120

Well-known member
Sep 22, 2011
197
I used to have this happen every year... I would open my pool and CYA would be 0. No one could ever explain it but people told me it happens sometimes. Just use pucks initially to up your stabilizer numbers.
 

dwhitt

Member
Jun 6, 2019
10
Pasco, WA
I used to have this happen every year... I would open my pool and CYA would be 0. No one could ever explain it but people told me it happens sometimes. Just use pucks initially to up your stabilizer numbers.
Thanks for the advice... I have been confused as to how CYA was at 70 at the end of the year and now with no reading? I have some pucks so I will try that route... I really do not want to get into a large drain situation again.
 

PoolGate

Gold Supporter
TFP Guide
Jun 7, 2017
4,710
Damascus, MD
Use an aquarium ammonia test kit and test for ammonia. You should have none. I know you show chlorine but is the pool able to maintain any chlorine after about 20 minutes?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
31,291
Laughlin, NV
I am wondering if my CYA levels are below 30 possibly at 15 to 20?
If the pool is maintaining any chlorine level with sun shining on the surface, I suspect you have some CYA in the water.

Assume you have 20 ppm CYA. Add no more than 20 ppm worth of CYA and then test 24 hours after it is fully dissolved from the sock.