CYA is at 40 and pool is covered to protect from UV, but I am going through a lot of chlorine

[Pooltwins]

27,000 gallon in ground plaster pool. Located in Northern California. Pool is covered during most of the day (last two day test it has been completely covered) so UV exposure is very small. Using Pool Math app I added approx two gallons of chlorine two days ago and today it is registering 0. All other measures (pH, Calcium and Alkalinity) are all in line. It has been hot...90-100 every day.

I have done my own pool maintenance for two years (using the TF-100 test kit and a digital pH meter for measurements) and used Pool Math for determining additions. This is the first year the chlorine is going this fast. Any thoughts?

 

[PoolStored]

What is your CYA level? Post a full set of water test results.

How old are your reagents?

I would do this test tonight...Link-->Overnight Chlorine Loss Test

If you fail the OCLT, start the SLAM process...Link-->SLAM Process

 

[Pooltwins]

CYA is 40, pH 7.65, TA 70. Reagents are between 6-9 months old.


I forgot about the overnight test. Thank you. Will try that tonight