Everyone was recommending flexwatt though. It's cheaper than a standard UTH and I am not sure if a UTH would fit the 12 qt container. I guess maybe a mini one would? I will have to do some browsing at the pet store then.
Also, if I get a flexwatt would a 1 foot strip of 4" be okay for the 12 qt container. Of course I'd probably have to cut it to appropriate size, but just curious? Or should I get more?