My first post, I am honored be be here. I've owned a pool for many years and have not come across this problem before. Let me back up a few months, I spend a lot of time and care closing my pool every year and it normally opens up clear. It is typically science opening it, but in early winter I had a rather large tree branch blow off and it landed in the pool and busted the cover allowing dirty water into the pool when I replaced it. When I opened it this year I did all the normal stuff, removing leaves, there were only a small amount, about like normal, ran my vacuum until my inline filter never picked up any more debris which again was minimal. My water was not green but it is very cloudy, when I opened it I could see down around 3 feet. Here is where I am at a loss, I raised my PH and lowered by Alkalinity, added shock up to 5ppm, then my stabilizer. Normally I can open the pool, balance it, add 4 gallons of shock and it runs trouble free with just minimal chemical adjustments along with the tabs. This year I had to add 16 gallons of shock to balance it and this morning when I checked it the FC was gone and so was the CY. I am sure the pool has some algae but not to the point it has any green color. The pool store is telling me I need to put algaecide and add something he was trying to sale me to lower the phosphate but in all my years I have never had to add either of them to balance my pool, and I only use algaecide after the pool is open to prevent algae. I have added more shock than I do in a normal year. Do you have any idea what I can do except for buying more shock? If I add more shock will it recover any of the CY?