I am going to partially drain my pool. CYA is at 113. Its 27,000 gallons. My question is do I close all the valves on the pumps and filters? Turn the pump off, yes of course. What other gotcha's are there as I haven't done this before. My mistake as a new pool owner was leaving my tabs in over the winter when there is little burn off and not checking soon enough. Lesson learned. Any guidance is appreciated. Thanks in advance.