I'm pretty sure Sbarbee54 was referring to Montmorillonite clay. I just bought a bag of SafeTSorb a few weeks ago and am trying it out. Do a search on this and other forums and you will find others that have been using it and other similar products for quite a while now. I also use Montmorillonite clay in my ADA substrate & flourite tanks. And........I even take a spoonful of it myself in a glass of water each day. Ya, it's tastes just like mud. But Most animals eat some sort of mineral, so I thought maybe they were smarter than me and I'd give it a try. At least it's not supposed to have any adverse effects.