Tap water in Edmonton?

[blacknife]

Chloramines for one. Be sure to treat the water with prime or amquell.

I think it depends on a few things. Using ro/di water just eliminates a few more variables of what is going into your tank. For starting out it "may" be ok. If you start having algae issues that refuse to go away you will start to wonder what really is in that 10-100+ ppm disolved solids in the water.