clean up crew with triggers

[blkmonday]

i have a 72 gallon tank with a huma huma and a niger trigger and a domino damsel. i have a serpant and a chocolate chip starfish.needles to say my clean up crew has been eaten. is there anything i can get that will help clean the tank that will survive with these tankmates.
i have heard large hermit crabs will work...any particular kind?
any suggestions would be appreciated thanks

 

[blkmonday]

i was also looking at urchins and large snails...would they be a good alternative to having small snails and crabs?

 

[jeremye83]

I did a humu humu and a niger for 2 years with snails.. lose one once in a awhile but for the most part they left them alone.