Amazing thing, a little over a year ago (7/19/13) my CYA was over 200, maybe even 300. I stopped using pucks and started the BBB method. After months I finally got it into the range I wanted, about 50 then into the 40s and 30s. Months went by and I didn't give it much attention. Over the winter I measured it in the low 30s so over several monts I dropped about 3 pucks in my chlorinator and on March 1st of 2014 I measured a CYA of 55. I didn't measure it again until about a week ago. We have had lots of rain and I have had to pump out water, prior to that I was adding water from the garden hose. I just don't know when it plunged down into Nowhereland.
So on 7/21/14 I put dropped in another puck and it's nearly dissolved today. I measured CYA for the third time this week and today I am still filling the tube to the top and can see the dot quite clearly. Added another puck this morning.
It's just weird to be on the bottom end of this issue. I would much rather be here though than at 200 plus, no doubt! Which is why I am adding a single Chlor puck at a time and measuring daily. I noticed my Chlorine consumption seemed to be rather high, about 2.5 gallons per week since it got hot again down here in Florida. I attributed it to the heat and huge amounts of rain, plus I had a lot of organics in my pool due to broken and missing screens in the enclosure. Got that fixed so there are lot less bugs and leaves now. So now I am thinking the chlorine consumption could also have been due to my low CYA levels? I mean not just low, there is practically no CYA and my pH was hovering around 7.9 for the past few months. It is now right at 7.7.