Reef crystals is what I'll be using from now on. I don't know that it has hurt anything, as the few corals I've lost I lost right after the move to Des Moines, but with oceanic my Ca is at 550 and alk at 3 meq. I've been using it for ages and haven't seen large problems, but I'm going to keep my parameters more in spec from now on, will only use oceanic for water changes when calcium is low.
Anyway, yeah, a bucket of reef crystals. If it's 40, that's fine. Much more than that and I'll just buy a couple from fosters smith. I'd like to support SOM though, so hopefully the price is right!