Thanks for the link. I see he also sells ExoTerra Heat Wave UTHs too. I think I'll go with a dimmer. I'm also thinking I'll need to move Sobe to a different tank when I install the UTH with the dimmer until the temps regulate. Do I put the digital thermometer probe on top of the mulch, part way in the mulch, or against the glass bottom? I guess I feel a bit nervous about using UTHs.