Can heated pool water affect CYA?

[MJF54]

I installed a heater on my 15' round AGP last season. I fought high cya last year but since winterize and refill this spring my cya was at 40 on start up.

Since start up this year we did have a very warm spell and lately have had a lot of rain necessitating a few drain downs of 3-5 inches. We also are using the heater more this year than we did last year. I have it set to 86 degrees. My cya dropped once to 10 this year and I added stabilizer in a sock at the return to return it to 40. In the past six weeks it has dropped to 0 again. I have some Tri-Chlor pucks I can use but want to stay TFP method and usually add 12.5 % bleach and MA to keep things in line as it has been successful for me for the 3 years we have has the pool.

Is there an issue with something chewing up the cya or should I just call it business as usual and add as needed? I'm leaning towards the Tri-Chlor this week just to see. I also have stabilizer available too.

Average readings are:

FC 4-5
CC 0
PH 7.6
TA 110
Cya 40

Thanks,

Mike

 

[tucsontico]

I installed a heater on my 15' round AGP last season. I fought high cya last year but since winterize and refill this spring my cya was at 40 on start up.

Since start up this year we did have a very warm spell and lately have had a lot of rain necessitating a few drain downs of 3-5 inches. We also are using the heater more this year than we did last year. I have it set to 86 degrees. My cya dropped once to 10 this year and I added stabilizer in a sock at the return to return it to 40. In the past six weeks it has dropped to 0 again. I have some Tri-Chlor pucks I can use but want to stay TFP method and usually add 12.5 % bleach and MA to keep things in line as it has been successful for me for the 3 years we have has the pool.

Is there an issue with something chewing up the cya or should I just call it business as usual and add as needed? I'm leaning towards the Tri-Chlor this week just to see. I also have stabilizer available too.

Average readings are:

FC 4-5
CC 0
PH 7.6
TA 110
Cya 40

Thanks,

Mike

Normally, the only way for CYA to decrease is draining and refilling the pool. If you are draining the pool due to excessive rain, I'll bet you're decreasing the CYA due to this "rain drain". However, in rare conditions, the CYA can be converted into ammonia. Again, your CYA is most likely decreasing due to the repeated draining and dilution from the rain.