I opened my 35,000 gal vinyl pool about 3 weeks ago. I converted to BBB after learning about pool chemistry from this site last season. I like knowing what is happening in my pool and not relying on someone caring more about making money off of me rather than caring for those who swim in it.

After getting the pool cleaned up (it is very clear now), I'm having problems with maintaining any chlorine level. I can get it up to 4ppm FC in the morning but it is at 0 in the evening. I did not have this trouble last year albeit with very high CYA levels (over 100). Now after several partial drains and refills, I have a more manageable CYA number (I thought it was ideal) but I can't believe that I can't hold chlorine levels for a day. My latest numbers are:

FC: 0
CC: 0
TC: 0 (I'll be adding more bleach once the sun is down)
pH: 7.2
Alk: 80
CYA: 40

I run sand filter 24/7 and there is very little organic material and no bather load right now. Like I said, water has looked good for past week and still not able to hold chlorine. I'm dumping about 3- 3.5 gallons a day to try to keep above 3ppm. That is not what I wanted after conversion to bleach.

Any thoughts?