Interesting. I used it once when I first got into the hobby 7+ years ago as it was more popular back then. Haven't seen much of it until I recently saw it again. Not going as far as saying it's on a come-back, but at leave I noticed it. Maybe it just didn't go anywhere.
Moving on. My last tank was successful for me and had it inside. Anecdotal, but I will buy again however my new tank is significantly larger.
The question is to replace or rinse. I'm not really looking for the trace element part of it since I may be getting what I need through trace dosing + CaRX. I'm actually looking at it from a bacteria perspective being sourced way out in the blue ocean. Potentially increasing bio-diversity. From that perspective, I'm assuming the bact will seed and go inside my tank. Eventually limiting when it can't compete against any other existing bact. already present. Theory is it'll do all the goodness while it can while trying to replace and either successfully earns it's place amongst my current tank bio-diversity ... or get out-competed and the mud bact. disappears.
Anyone else looking at it from this perspective? Or all for the packaging stated trace elements. Buy and continue to replace for the trace or seed one time and hopefully it'll continue to add benefits.