Bought house in April this year. Have a rectangular IGP with about 25000 gal water with deep and shallow end. Firs pool I ever owned, it's about 10 years old with sand filter and 1 hp Hayward pump. Had no idea about anything and could not understand the pool store (because they have no idea about most of the stuff). Pool opened cloudy, and would not get better. Read a lot of pool school and dropped 10 gal liquid chlorine 12% followed by some clarifier (probably should not have used), and eventually pool got crystal clear and everything was within perimeters. So far I use test strips and go to pool store weekly for liquid chlorine supply and computer testing. Currently only use baking soda and borax if needed, started with bleach but pool store chlorine seems to be cheaper and double strength. Added CYA to pool by using tablets. Learned everything here, so thank you guys all for all the great advice!