I may be the odd man out here but I do not trust any heater controllers, especially the built in ones or even the Apex or RK controllers. The built in heaters use such cheap components that its not worth the risk if you have a system of any size. For the Apex and RK controllers I just don't trust such a complex controller system to manage something as basic as temperature. I am fine for them "monitoring" temperature but controlling it is a different story. Just way to many things to go wrong. For temp control I only use the Ranco controllers. Both of my systems have redundant heat and cooling on two separate GFCI Circuits, while the heat for my large fish system is even battery backed up (its natural gas so only a recir pump). In order to not have a single controller be a point of failure and cook one of my systems I run two Ranco controllers in series for the "A" pair of heaters and another set on another GFCI for the "B" pair of heaters. For cooling I have fans on the A Ranco's and a 1/3HP chiller on the B Ranco's. Here is a shot of the control panel for my SPS system. I have been using the Ranco controllers for nearly 6 years now. Between my two systems (4 each), my QT Tank and WC tank I have 10 Ranco controllers in service and two spares sitting on the shelf just incase. Over the 6+ years I have used Ranco, I have only had two break down on me. One the relay crapped out and the other one would not save the temperature settings anymore. Both of these were on the same pair of controllers in my fish shed and I suspect it was due to moisture getting into them as they sit close to the sump and showed some signs of moisture in them. I need to relocate them and seal that pair better as I did not do a good job on that (it was my first pair). Either way I consider this a really good track record and over that entire time I have never had a heating or cooling issue. Its not a cheap price to setup things this way but considering how much time, money and affection have gone into my tanks I would just hate to think of cooking everything in there because a cheaped out on temperature control. Some of my fish I have had for coming up on 9 years and I would just hate to loose them.