I know all of you have huge tanks so you use a good amount for water changes. Well I just have a 20 gallon freshwater tank that gets tap water and my 29 gallon saltwater tank that I currently just refill my water cooler 5 gallon bottle. Looking into a unit. What are the maintenance procedures for these units. My girlfriend drinks a ton of water and refuses to drink tap water so I'm starting to research these units. Any help would be awesome.