first reef tank - RO, DI & salt mix questions

[dcmoore]

I'm totally new to SW tanks. I have a 20 gallon tank with a 10 gallon sump plumbed and ready to go with a bakpak2 skimmer. I'm ready to add water but I'm not sure how to proceed. First there is the RO or DI issue. I can get a tap water DI filter at J&L (I'm on Surrey water) or I can buy RO water at Save-On Foods. Ocean Aquatics also sells RO water. I'm somewhat hesitant to buy a RO unit at this time. Is DI "good enough" or do I need to go with RO? Has anyone had any recent experience using RO water from Save-On? I say recent because I believe that they recently switched suppliers.

Then there is the salt mix. Instant Ocean, Kent Marine, Seachem or Tropic Marin appear to be the choices. Is one going to be more suitable than the others?