I am cleaning and refurbishing my old MacClean chem-free iron filter from the late 80's or so after some incompetent service guys messed it up. I'm nearing completion but don't know what kind of media was used in the tank. Although the last guys to change it left out the stone pebbles it normally used them for a base. The fine media looked like white sand when new. MpH Adder is no longer available. Is calcite granules the same thing? Thanks for any help. The water filter companies all wanted to install a double tank 3-4 thousand dollar setup but this MacClean filter gave us good water. This was our second one after some damage to the first one.