Expected rates of chemical changes in Arizona summer

[Copernicu]

My FC, pH and CYA change over time. FC goes down over time, pH goes up over time, and CYA goes down over time. I had some leaks that were fixed and I am wondering if I still have a leak and/or if I am not maintaining proper levels.

What should I expect during an Arizona summer (100 degrees F or a lot more, lol) as far as: 1) how much should FC fall per day, 2) how fast should pH rise over time, and 3) how fast should CYA fall over time.

And a follow-up question.....when you are SLAMming a pool, is it normal for FC to fall faster per day compared to when FC is at normal (non-SLAM) levels?

Thank you.

 

[Texas Splash]

To your questions:
- FC loss hopefully no more than 4 ppm per day unless you have a swim party. When in doubt, do an OCLT.
- PH rise each week to some degree not uncommon. How fast and how high depends on your TA and any amount of aeration that can cause the pH to rise more. Fill water also influences the pH and TA. I like my TA between 50 - 80.
- CYA can degrade anywhere from about 5 - 10 ppm per month. Every pool is different, so it's not a perfect science. Stabilizer is funny that way. You can have very little drop in June, then a large drop in July. If you check at least monthly you should be okay.
- During a SLAM, yes. You can expect the FC to fall quicker. This is due to the excessive free chlorine compared to the available stabilizer.

Hope that helps.

 

[proavia]

Expect to lose about 4ppm FC per day in summer - higher with a higher bather load.

In PHX in summer - try a CYA of 50 (or even 60) and target the upper end of the FC range for that CYA level according to the FC/CYA Levels.

With our intense sun and UV, a CYA of 40 just isn't high enough.

When using liquid chlorine or a SWG, let your TA get down to the 50-60 range. This should slow your pH rise a bit.
Be advised, our fill water TA is around the 120-130 range. With our high evaporation rate, you will have to watch the TA and pH to keep it in check.

 

[Copernicu]

Thank you very much for the responses.

I have been adding a gallon of liquid chlorine each day, and I don't recall having to do it that often in previous years. My levels today were:
FC 7.5
pH 8.2
TA 80
CH 300
CYA 30

My plan is to raise CYA to at least 50 so hopefully I won't have to use as much liquid chlorine. I'm also going to try to get the pH down to maybe 7.5. I do have to monitor pH and CYA because, over time, my pH goes up and my CYA goes down. It feels like my pH likes to hover for a while at about 7.8--if I get it lower than that, it seems to go to 7.8, stay there for a while, and then eventually goes up higher.