with that much water going through them, how often do they replace their filters? i'm sorry, but the more i can control the more i can trust in the person working on my system. I don't have to worry about someone not changing the filter, or if they are just bottling pond water with a filter.
if you're in this hobby, you should know its expensive, but the right tools will make it less expensive in the long run, get an ro unit if you have the room for one.