DIY Live rock questions

[BCOrchidGuy]

Lots of videos and advice on You Tube so my questions are hopefully simple.

Instructions tell me to use portland cement but I've seen a few people say any cement will do... thoughts?

Water softening salt is used in a lot of the recipes so I'm wondering if anyone has a local source for this and finally the oyster shell, where will I find it? I was thinking otter co op but haven't had the time to call them yet.

D