Closing in-ground pool that eats CYA?

Ben_G

Member
Jun 9, 2018
12
Indianapolis/IN
Just wrapping up the third summer with my pool. I’ve always had trouble with CYA disappearing. Apparently it is susceptible to whatever baddie that turns CYA into Ammonia. When we opened it this year, it took over 30(!) gallons of 12% bleach to balance all the Ammonia that had built up over the winter. I’d rather not have to do that again.

Just this past week, I noticed my chlorine wasn’t holding, and sure enough my CYA had dropped to zero and I had 0.5 PPM of Ammonia according the pet store fish tank test. I slammed the pool and added enough CYA to get the pool up to 20 PPM.

So (finally) getting to my question. Would it be better to raise the CYA over the winter in hopes of keeping the chlorine useful? Or would that just act as more feedstock for the baddies and make my Ammonia problem worse next spring?

hanks for any advice!
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,368
Tucson, AZ
Well, it’s a little unusual for that bacteria to build up in your water in the first place. It would indicate that your pool FC levels are dropping too low this allowing fir the bacteria to get into the pool.

Are you testing regularly and maintaining a proper FC/CYA ratio?

Aside from that, properly closing your pool AFTER the water temperatures drop below 60F and opening up the pool in the spring as soon as the water gets to 60F, wound eliminate the possibility of getting a green pool that can breed the bacteria that wound generate ammonia.
 

Ben_G

Member
Jun 9, 2018
12
Indianapolis/IN
I’d checked the CYA a few times over the summer, and it had held. I did let the FC drop which I’m sure brought on this last bit of Ammonia.

The pool has never once been green, even when it has Ammonia. I didn’t have the Ammonia test kit last year. I guess I’ll double check it is at zero when the pool is closed, and make sure to open it on the early side next year.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,368
Tucson, AZ
Consider following the directions in this Pool School Article -


Many people that follow this advice report little to no trouble when opening up a pool. If the pool is properly closed for the winter and kept clean just before covering, there shouldn't be any chance for ammonia producing bacteria to proliferate. Opening early and getting chlorine in the water before it warms up is key.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
34,430
Sebring, Florida
+1 what Joyful said above. adequate chlorine prevents the bacteria from existing in your pool in the first place.

I would suggest following standard closing practices of not closing until water temp is below 60, then bringing the FC to SLAM value and close it up.

Open as early as possible in the Spring