With the RO/DI units, it says it makes 50 or 75 gpd. Once it does like lets say 30, can you shut it off that way you dont have like hundreds of gallons of RO water sitting around even though you only put in like 15 every week? And about buying the RO water, if you put in like 10 gallons every week, do you have to buy 10 gallons every week? Or can you buy like 20 and then you dont have to go every week to the pet store?