Looking for RO/DI Solution - Calgary

[molotov]

Hey all, I live in SW Calgary and was wondering what my best option for a reverse osmosis system might be. I'm looking for a system and was wondering if I might be able to get away with just an RO system or would I be better off with a RO/DI system.

I wouldn't mind running a supply line to my fridge in addition to supplying water for my aquarium.

Another concern I have is waste water. It kind of makes me sick to waste water as it's such a precious resource that we tend to take for granted. From what I've read the less stages you have the less waste? Also the less GPD the less waste.

All suggestions are greatly appreciated.