Hello all. I'm so happy that I came across this site. It's provided me with a glimmer of hope in an otherwise dismal summer for my pool. I'm new to pool ownership as it came with the house when I bought it last fall. I've battled heavy algae for most of this summer. In working with my local pool store I've managed to dump all sorts of chemicals into the pool with little results to show for it. I've also replaced equipment and replaced the sand in my filter twice as per their recommendation. As a final effort we decided to add 6kg of power chlor over the course of two days. I was excited when I saw the algae disappear however it came with a major drawback as my CYA level is now 180-200ppm depending on who is doing the testing. The pool store failed to mention that this would happen. In fact they are still unsure of where the CYA came from even after I showed them the warning on the bag. Had I known then what I do now I would not have proceeded with stabilized chlorine to solve the algae issue. It is what it is now. I'm currently at a FC level of around 15ppm and I'm starting to see some algae forming again. My question is, what is the best way of getting my CYA levels in check? Pool store is telling me to use CYA removers but the pool school on this site says dilution is the only way? I'm looking at 25hrs of pumping to remove 7000gallons of water (Pool is 10400gal). Is this the only way? Do I need to remove/replace at the same time? Is the pool safe to use if I don't bring these levels down? I apologize for the long first post. Feeling a bit frustrated. I also have little experience with forums of any kind so hopefully not breaking any rules of etiquette. Thank you all in advance.