I used the probiotic salt for about 6 months, i replaced reefers best with it, IMO no change in my tank, it is a good quality salt, did the probiotics do anything? Not that I noticed.. It mixes up really well and has consistent levels which are nearly at NSW and matched the levels I was dosing to.. The downside for me was having to use it within 48 hours, I like to mix big batches and store for several weeks.. So I switched to their reef salt which has the same levels just no probiotics and again I'm more than happy.. It's easier to use with consistent levels..