RO/DI Membrane question

[bigmac]

I'm getting organized to start another tank after a move into a new house. I have an ro/di system that I had running on my 90 gallon. My question is this; does anyone run theirs without the membrane which would then rely on the sediment, carbon and DI resin to purify the water? An experienced reefer told me once that he never used the membrane at all; due to the amount of water wasted.
Has anyone tried this?
Calgary water isn't really that bad; but I'd like to hear from anyone that has tried this.