Mixing reef crystals

Hey Guys I was just mixing some reef crystals that had some moistue on it making it blocky, I know this makes it harder for the salt to mix, But I made 3 batches of 5 gallon buckets of salt and there seems to be small residue of white on the bottom, Is this all the calcium magnesium and stuff? Should I just use my salt or wait? ( I was mixing it last night for a hour or two with a power head, and for sometime today)

I tried adding a heater to one with a power-head pump and I'll see how that goes.

any help is appreciated.