I'm not closing my pool yet because it is far too warm but I am wanting to be prepared for when I do. I am clear on all of the steps listed in this http://www.troublefreepool.com/content/145-closing-winterizing-your-above-group-pool except one. On the algaecide I currently have some Poolife brand Defend+ from when I was being pool stored that lists on the active ingredients 20% Poly[oxyethylene(dimethyliminio) ethylene(dimethyliminio)ethylene dichloride]. That's exactly how it is spelled and written and does not list any metals. I am assuming that would be Polyquat 20. Should I just scrap that bottle and get the Polyquat 60? This will be my first closing and next spring will be my first opening of an existing pool since I put it up. I definitely want to do an algaecide because I am 60 miles north of Dallas and we can get some cold spells but the temps can range pretty good too. I am hoping to open up to as clear of water as possible to convince some friends of mine that are still being pool stored that this is in fact the way to do things. I figure they will open up a swamp because the pools are both at around 75 degrees but we will still get warm spells and they are getting ready to close theirs already. So if they do open up to a swamp and I have nice clear water then I bet it will be the final nail in the coffin with the pool store for them...lol I know I sound like a jerk but I just want them to quit throwing $$$ at the pool store and still having algae. Thanks everyone!