hermet crab question?

I have had my tank setup now for about 4 months, I went and got about 10 wild hermit crabs from galveston bay they are pretty big, I need to know about what size crabs would ya'll prefer and what do you think about them bieng wild, would they destroy any corals, and they leave alot of waste on the sand bottom, how do I get rid of that, I'm sure that can't be good for my tank. Is there any fish or inverts that eat that?
 
Big hermits tend to be destructive, so most people don't put them in reef tanks. I don't know if some of the smaller, less destructive species, like scarlets and blue legs, occur down there, but they would be preferable. Some people consider even the small species to be risky.
 
From a company called Tampa Bay Saltwater. Nice folks, good rock. The rock has tons of sponges, corals and macroalgae on it. Also had quite a few mantis shrimp and I am still trying to get rid of a few hairy crabs after a year.
 
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