Aye, mass is always an issue! As for under tank heaters, I have never used them for a reason.

My main argument against them is that in the wild, the heat input to a system comes from above. I have seen more horror shows related to UTHs than any other heating method. If I had my way, I would outlaw the darn things.


(Note, we actually have an article in the works that covers this subject in depth, it will be available soon here on frog forum. It covers substrate choices and drainage issues in detail.)