I tested my CYA the other day because I went away for a few days and left in a floater with some chlorine pucks.

I just wanted to see how much, if any, my CYA level went up. I used a Taylor 2006c testing kit. Before I left, my CYA was holding at 50. Upon my return, my tests show that it was around 100 now. I didn't think it would have gone up that high, so I had it tested at the pool store. Their test says my CYA is 35. I am not sure why there is such a big difference. I tested it again the next day, and that test showed it to be 60.

Why the big swing???? Is this test more of an estimate than anything? I ask because the level at which I need to hold my chlorine is affected by what the CYA level is.