Coral going downhill? Help!!?

Yes of course! So i've been using reef crystals salt for a while now and ive been using building blocks for added nutrients. Well I think the building blocks were dissolving too fast anyway and then once i started using Oceanic salt, that is when it all of a sudden started having problems because (and I dont understand why they dont fix this problem with their salt) it is low in alkalinity buffers and very high in calcium so if you use it without adding buffers your salt becomes like mine.. low alk and high calcium and then your pH go's out of whack which of course pisses off your corals. So I just did a BIG water change, like half my tank with some basic "Natures ocean" salt and that put things back in line, now my corals are slowly opening back up. The only thing that im still waiting that may not make it are my blasto's. I trust Eric when he says that Oceanic is a good salt but you have to understand that it is low in Alkalinity buffers so everytime you mix salt your going to have to add buffers to it. So I guess moral of the story is... too much of a good thing can be bad. And make sure you know what you are putting in your tank dont just assume the manufacturers have figured it all out for you.