First time ever closing. We are getting ready to get a real frigid cold spell (overnight temps dropping to the high 20's for the next week, beginning this Monday night, with day time highs only in the 30's and 40's). My situation, I don't have a clue what I am doing. Went to a poll store today and they advised some shock wave, Sea Klear 90 day Algae Prevention & Remover, Pool Magic and a couple of Gizzmo's and some plugs. Will these things really do the job, or am I just sniffing in.the wind here? Is this all I need to close?