May I be frank:
Priority 1 is your water source. I lived in Calgary I know what the water is like it's hard amongst other things.
Don't think about it, buy it ....a good RO/DI filter.Po4 shouldn't be an issue with a new system unless you're using live rock from an older system and the water supply.
I hope this helps patience is the key ingredient
FYI
http://www.calgary.ca/docgallery/bu/...ity_report.pdf