Hi, I'm new to this forum. I have a 25000 gal Gunite plaster pool. The pool is over thirty years old and is still in good shape. However, after a drain and acid wash 2 summers back my son only used 3 inch Leslie's pucks to maintain the fc using the std oto test, but sure enough we started having algae problems last summer. I had the water tested and the cya level was over 100. So using the info supplied here I just stopped using pucks and just used 10% bleach instead slamming the pool and it did work got the algae under control. Ive been using bleach and acid to maintain very high levels since late last summer.
I was planning to drain the pool to make some minor plaster repairs and get the cya level to about 30 or 40 after refill and then use the bbb method for maintenance. I took a sample of water to leslies and when he tested the cya was back down to 60. I was very surprised. I didn't know that the cya salt could breakdown
The sales guy said he was told that uv does break it down with time. Does anyone know if this Is a fact or will draining the pool still be necessary.
Thanks for your hep in advance.