Please read above. The Hydor Mini Heater referenced merely increases water temperature a few degrees above room temperature (there's even a link for you to click).
Originally Posted by HypnoticAquatic
this just isnt correct it all depends on the wattage and the quality of the heater. there are heat pads that do work just gotta look into other fields such as keeping reptiles or growing seedlings its all depending on the wattage and the temp vs ambient temp. you could have a good tube heater not work due to it being out of range but that doesnt say that it doesnt work ya know?