Here are some pics of a saltwater tank that i setup for a few days and fed a pet crab from our local fishing hole.
To keep the water cool I put it under a window so the cool air would drop on the tank and keep it from over heating. It actually worked. the other equipment that i used was a filter, aerator and a thermometer. After the first day, the crab grabbed the lid on the filter and removed it and started actually feeding on the filter insert, which had all the dead critters, it was like a all you can eat buffet!!!
Alex Stuart
Alaska ROV Systems
.I only get blue-legged crabs there though 
what type is yours?? :mrgreen: