I am not super privy with plumbing stuff, but perhaps I could figure how out to put it in to the plumbing like you said.

I am going to be running an ebb and flow... and my resi will have 100 gallons in it... which will be changed once a week, maybe a little more often.

I know some R\O machines could fill a 100 gallon resi in reasonable amount of time (under 10 hours)

I'm willing to spend like $400-$500 on the machine, I think I'll get that money back in yield pretty much immediately. The installation on these things can sometimes be stupidly expensive, but perhaps it's worth it to get it put direct into the plumbing line huh?

Could I hook a regular hose up to it and then put that hose into my resi? I would likely run the r\o for a few gallons per day just to keep it working smoothly, but the majority of it's use would be in a 12 hour period.