I seem to have missed the beginning of this trend, only stumbling on it by chance after using similar clay media for growing plants (out of water!). I thought I had a brain wave when I looking into using it, only to find I had been beaten to the post. Overall it seems alot, I mean a hell of a lot cheaper than most aquarium substrates working out roughly half the price. I currently have 2 tanks, 1 4ft and 1 6ft. The 6ft foot in question is to be the victim of change to the new substrate and I will keep you posted on how its going. It might be worth adding for all you aquarium keepers out there that Takashi Amano used the stuff with great effect. He has now got his own company which specialises in various top end components for the aquarium. One of his products happens to be a filter substrate which is very, very much like AKADAMA and offers the same properties. Who knows this may be the cat out of the bag in terms of cheap but very effective substrate, at home in both the base of the aquarium and the filter. http://www.adana.co.jp/_e_product/50_index.html I intend on running a Fluval FX5 full of the stuff added to the 5 bags for the base of the aquarium..