CYA - what am I doing wrong?

[VinceL]

We've had our pool since 2012. Every year seems to bring some new challenge...some major, some minor.
This year's challenge is CYA. I just can't get the CYA level up.

Here are my test results from today:
FC 3.5
CC 0
TA 60
CH 160
pH 7.5
CYA less than 20 (I can still see the black dot with the tube full)

We had a bunch of rain lately which caused us to lose some water through the overflows (certainly explains to me why the TA and CH are a bit low). The FC of 3.5 is where I want it (we have SWCG). We also have an ORP sensor so I like to keep the CYA to a max of 50. Over the past few weeks I have dissolved about 6 lbs of CYA in a sock in the skimmer, yet I haven't been able to get the CYA up to 20 let alone 50 (even before the recent rain). Pool math says that for my pool, 5.8 lbs. of CYA would take the level from 0 to 50.

This is the first year I have had this problem.

I am running the SWCG for a higher percentage of time than in past years in order to maintain the FC. So, I am pretty sure my CYA is low.

 

[kimkats]

I almost always end up with little CYA in the spring. I also end up adding some towards the middle of the summer as well. With all of the rain we get it is to be expected!

 

[ajw22]

Wait until the rains stop to adjust your CYA. Sounds like you are losing it through dilution and your overflow.