I'm not exactly sure where they come up with those #'s. I have a 110 gpd unit and no way do I get 4-5 gal
/hour of of it. In the winter here with the cold weather, it takes me about 2 1/2 hrs to make 5 gal
You can setup the RO
so it will auto top off your tank, but you will also need a way to make water and store it for your water changes.