Best Salt??

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I use IO, never had sludge, never had film unless I leave it sitting for a couple of weeks with a heater and pump on then only slight.

I do supplement with Mg and Ca as find low out of the pail (one pail Ca 325, Mg 1100, Alk 11.2, another pail Ca 275, Mg 900, Alk 10.9) but don't find a a big deal, nor expensive as buy supplement bulk fr littlesilvermax.