Eytons' Earth: Natural & Alternative Medicine

[Jedi_sena]

This is going to sound bizarre, but I conduct food trials on local flora in search of suitable sources of ingredients for my all-natural line of land hermit crab food products called Crabotanicals. In the hermit crab community, the big buzzword is worm castings. Yes, worm pooh as a source of pet food and the crabs go wild for it. The most desirable worm castings are those worms fed a high concentration of volcanic ash. The claim is that the living organisms in the pooh are what the crabs are after, and it may be true. But I have a theory that it is the mineral content of the volcanic ash that attracks them which led me to start researching clay. I am just beginning this research, so bear with me, I'm going to sound like a complete idiot for a while until I get a handle on what this is all about. A gal is donating some cosmetic-grade clay varieties for me to test on my hermit crabs. Couple of questions I'd like to run by you all:

Hermit crabs are very sensative to metals, and particularly rust. Should I be concerned with the red morocco clay's russet coloring?

Since crabs are scavengers, they aren't very picky about the quality of most foods. Is there a great difference between cosmetic-grade and food-grade clays? Enough difference to be concerned?

Also, if the trials are successful and clay turns out to be a viable supplement product for hermit crabs, where would I find the most reasonably priced clays if I were to buy increments of 1lb of each variety?