I just purchased 25 turbo snails for clean-up in my reef. I feed my tank and fish on a regular basis. Many of the turbos were immediately attacked by the various hermits in my tank and now after a week I think all but 2-3 turbos have fallen as appetizers for the damn crabs. Is this typical and do the hermits contribute enough in maintaining cleanliness of the tank to justify having them. Am I better off with just snails or a mixture of crabs & snails. Advise is welcome 