Hmmmm--Like Ed, I get a bit annoyed at some of the posts I see here, especially those from folks who have had little or no experience with the species involved. To placate myself I say, I guess that they are well-meaning, but...
I have had a hellbender in Florida with no chiller for more than 15 years now. It was a "dead" creature, found floating upside down and seemingly lifeless in the aquarium of a Miami dealer. I retrieved it, thinking it would go to a University study collection, but just as a precaution, put it in a fish bag with some fresh water and stuck it under the air conditioner vent in the car. By the time I had driven the 350 miles back home, the little creature had revived and I had an 8" long hellbender to concern myself with. It went initially in a 15 gallon tank with hide rocks and a very standard aquarium filter. On a diet of worms and minnows, it soon outgrew this tank and went into a custom 50 gallon "low" tank, still with very standard filtration (a powerhead on a sponge) and more hide rocks. It has been there since, taking fish and worms from my fingers, and living in "room temperature" water. I know of a dozen or more others that have been kept pretty much the same way.
Yes, I expect a barrage of comments re my "horrid" husbandry methods. But I submit in advance that it is obvious to me that many of the comments I have seen have been made are by those with little (if any) practical experience with this salamander species. Rgds/Dick