Sand and stones. I don't like the stones I have in my aquarium atm, besides the fact that it's almost bigger than the crabs. And they love to move it around. I'd like to change it, the stones. Or really, I am going to do that later this weekend. But I've been wondering...

I read from other ppl that they recomend that you use a light collor on the stones so that you can see the crabs easier. But doesn't that bother the crabs ? And also, I've been wondering about sand. It looks very neat and soft, but would the crabs enjoy it, and how do you clean it ?