Big time daily chlorine loss

[Ronald U.]

Greetings. I have always noticed a large daily drop in FC during the summer. Up to 5 points is not uncommon for my pool. However, it seems to be even more lately. I target FC at 7.0 every morning. This morning's reading, pre-chlorine addition, was 0.5 points. 6.5 point loss during the day? Wow. Can anyone explain this? Does anyone else see this level of loss? True, I am in SE Texas, pool has direct sun about 9+ hours right now. Is there a solar cover that could cut down on my liquid chlorine usage? Thank you as always. I trust everyone is enjoying their pool.

 

[revitup]

I know the drill.
How are you testing? What's the CYA level? What are the other chem measurements?

 

[Ronald U.]

Today: FC 0.5
CC 0.5
pH 8.0
CYA 40 (last checked 3 weeks ago)
TA 110
CH 175
Salt 2400 (last checked 6 months ago)
Borate 40 (last checked 6 months ago)
I use the TFTest kit.

 

[mknauss]

Add 10 ppm CYA via the sock method. Test your CYA 24 hours or more after it is all dissolved.

I suspect your CYA has fallen some due to high water temperatures.

Get your FC up into target range ASAP.

 

[Ronald U.]

Thank you all. You are correct. My CYA is below 30, above 20! Adding now. Sometimes it seems I have to pose the question before I can do what is really needed to solve it. Regards,