Sounds like a cool project auto water changes patent that setup lol..Question though how are you adding the salt to the R/O water. I mean if your R/O water is already have the salt in it and is coming from a container mixed then defently cool. But if your just replishing with Freshwater then issues of course since everyday you would loose a gallon of mixed for a gallon of freshwater. But again if the new water is premixed ahead of the scheduled gallon swaps then COOOL