That tank is one of the moderators, Bill Harada. He has told me its very light weight stuff, really high CEC rating and its inert. I just couldn't find grey colored in WA state, or I would have chosen it for sure. Great price at $12 per 50# bag. You can find some more stuff on it by using the search forum tab. Its suppose to be nice stuff and is inert, not like soilmaster select which lowers KH/pH in a big way. There was a thread on it with links to info off the Krib I posted a week back in Substrate. And another link recently I saw showing mineral content etc of lots of different substrates. Turface was right near the top.
BTW, welcome to the forum __________. lol