Conrad Hoffman , Jun 16, 2004; 09:40 a.m.
Ok, I hate it when people don't answer the question, but I don't have a clue. I just bought a lifetime supply of carbonate for five bucks when buying stuff for the pool at our local hardware store. Ph increaser is nearly pure sodium carbonate (watch out, they sell bicarb for the same purpose- read the label) and works fine for photo use. It just isn't worth the trouble to heat bicarb and not be sure of what you've got, when the real thing is readily available for so little.