For that size tank, I don't think you have anything to worry about. These systems are usually operating at about a 3:1 rejection rate so you aren't talking about hundreds of gallons of water (once you complete the initial fill). If you do a 10-20% water change every few weeks you are talking about 20 gallons of water to make, or 60-80 gallons total. That is like taking a 10-15 minute shower. You just may have to change your prefilters a little more often so you aren't bombarding the RO
membrane with hard water.
My parents have ran an RO
system for drinking water off of their well for 20+ years. It has never been an issue.