The Right RO/DI Unit for me..

That is precisely what it means. But both will produce equally pure water and thats the misperception I was wanting/trying to avoid.

 

2-3 gals per hour?

are there any one that do more...i have a 72 gals and that would take 24-36 HOURS to fill my tank and even longer if you include the sump. crazy

 

Water production depends on more than the membrane. Lower pressure or colder water will drop the production. The units are rated at optimum conditions and very seldom are they met. You can find 150gpd hobby units if you look. Pay a little more for them. Or, get a 75gpd unit and add a "water saver" feature to it where you add a second RO membrane that is fed by the waste water from the first membrane. Saves water and produces almost twice as much per day.