This question has probably been asked before but I'm not readily able to find an answer. I plan on getting an inflatable hot tub and was wondering if I can just use a sump pump from my already chemically balanced 20,000 gallon inground pool to fill up the hot tub? Can I just use the same rules that apply to my pool to balance the chemicals? Is there anything else I need to do different? I plan on draining it about every 3 months to exchange water.