Heater getting to hot.

So i noticed another member posting about issues with his tank temp dropping. Im having the opposite issue. I got home last night and noticed my tank temp was at 85.6 degrees. I immediately pulled my heater out and dialed it down. I believe the thermostat controller in it has failed as the heater was buring hot in my sump. Im guessing my heater has reached the end of its lifespan. The durrent heater is a 300 watt hydor theo. is that a good heater to stick with on my 120 or am i running to big of a heater? What are some other brands and wattage sizes to consider replacing this one with? As of now i have the heater dialed down to 75 degrees and appear to be running at a steady 80.3 degrees for the last three hours. I have a couple smaller wattage heaters to use as backup if hecessary. I appreciate any advice that can be offered.

 

I use a 300 watt eheim jagger which is one of the best heaters out there. They are longer due to only using a single element so it measures 15 inches long. I have a 2nd 200 watt heater to run just in case the other one fails and to take some of the load off of the main heater.

 

Thanks for the input. I used to run ebo-jager heaters on my cichlid tank. I assume eheim-jager is the same...just modified name. Appears as though eheim bought the old company out. The hydor i am running now was a hand me down from my dads old cichlid tank. I think i will take your advice and run two smaller 250 watt heaters. Thanks again. Also if anyone else still has advice feel free to reply. I like hearing everyones input.

 

I have a 120 gallon. I thought about two 200 watt units as well. I think the work load on two 250 watt heaters would be less though...maybe? Not sure what would be better for a 120 gallon...200 or 250 watts?