I have a lamp dimmer attached to mine but then again I have a UTH for 10-15 gal and my tank is 20gal. I have a probe right on the glass where it is because my bp always moves the substrate under his hide until he is right on the glass. after a couple hours of plugging it in and checking often i can get a steady reading at 90 right on the glass so i know hes not too hot but I check mine alot. I wouldnt suggest the dimmer route if you aren't home often to check the temp just incase something changes.