It appears that I have lost my CYA. Was it was the extreme heat and bright sun? Where did it go? It was just over 60 a couple of weeks ago, and yesterday evening it barely even registered on the two tests I ran. I could still vaguely see the black dot when the tube was completely full. I first used the solution I had in my old kit and didn't think the result could possibly be accurate so I tested again with the new refill solution I recently purchased from TFTestkits and got the exact same result. I have topped the pool off a couple of times due to evaporation but I certainly haven't replaced enough water to lose almost ALL of my CYA. I was afraid to add any more last night because I thought maybe something was causing my test to results to read wrong. I certainly don't want to overshoot it like it did early in the season. I'm totally confused! Please share your thoughts and/or explanations. My water temp is 82F if it makes any difference. All of my other numbers are good.