I've got the 5+ system from BRS. It's just the way it is. Making RODI
water is pretty slow unless you have really good water pressure to begin with (100 psi+). You can always get the booster pump or the add-on to change it from a 75gpd to a 150gpd system.
I usually turn on my rodi
system on when I get home from work and turn it off in the morning before I go to work. Usually gets me close to fill up my 45g brute trashcan.