About a month ago, I had water tested at Pinch A Penny and they said my CYA was around 90 or a little higher. I took out the tablets and haven't used them since. I had an algae problem a few weeks ago and got it cleared. I also recently purchased a SWG and got my new TFTest Kit in today. When I took the sample for CYA, the black dot never disappeared which means the CYA is low. How could it have dropped so low already. I know I did the test right.