Our CYA is 80, and I'd like to do a partial drain to bring it down. The pool calculator tells me I'll need to drain half of it to get it to 40. Can anyone tell me the steps I should follow to do this partial drain? I've tried to research it and am getting very confused by all the different information. Our filter has a backwash setting. Do we use that? A sump pump? Do we drain it into the sewer or into the ground? We have had tons of rain lately. Does that matter? A step-by-step explanation would be so great!