Hey, Ive been keeping chiclids/odballs for a while now. I recently started to test GH/KH my reading were off the charts at 14 drops for GH and 9 drops for KH using api test kit. I realized that my tap water is very hard and every water change raises my levels. I looked at the api water filter but, I have a 180 gallon fish tank and it filter water fast enough. Does anyone know what I should use to filter my water? Should I buy a reverse osmosis filter? HELP!