I have a 110 gallon tank that I'm currently trying to heat but while I was looking for one to buy I kept getting varied reviews. What would be the best heater for me to buy for my tank, on both accuracy and temperature control.
There are several reliable heaters; presently I would get an Eheim Jager, which was the last heater I acquired a few years ago. Other members will have reliable heater brands to recommend, but the important thing is wattage and number.
Assuming this 110 gallon tank is at minimum 4-feet in length, and more likely 5 feet, you want two heaters. These should be positioned at opposite ends, next to the filter intake at one end and the filter return at the other (assuming a canister filter). This provides good dispersal of heat. The higher wattage tend to function with less issues, and last longer; my 150w and 200w heaters purchased in the 1990's were still working with no problems when I gave the larger tanks away this Spring when I moved. I would suggest two 250w or two 300w heaters. The climate and room temperature factor in to this, as heaters are not intended to heat in really cold rooms.
If you have a canister with a heating element, this is ideal and eliminates separate heaters altogether; I had an Eheim Pro II with heating element on my 90g tank for over 20 years with not one issue.
I've always liked the two heater idea. It allows load balancing (as they each work less than one alone) and if one quits, the other can likely hold enough temperature until noticed so as to not lose any fish. However, if one sticks on, there could still be an issue. Some time ago I opted for a Finnex external controller with a 500w titanium heater for my 60g. I also have a Finnex external controller with an 800w titanium heater in my 110g stock tank in basement. Both work flawlessly.
As Byron points out, ensure you have sufficient wattage relative to the tank size as well as the anticipated ambient temperature. If going for two independent heaters in living space (as Byron points out) you likely want two 200w - 300w heaters.
I agree with the backstop. The consequences of a heater failing to come on gives you (at worst) hours and at best days to respond. Having a second heater obviously reduces that risk and greatly extends the time you have to react. The consequence of a heater failing to turn off can be catastrophic in a very much shorter time.
@AbbeysDad thanks for the kick up the wotsit. I have an external controller in one tank but not in the other 2. As the livestock in each of these is worth cinsiderably more than the cost of a controller I have now ordered another 2.
@Smilecentaur, if you have a canister without a built in heater I had a Hydor external heater that worked flawlessly for around 15 years. I still have it but its just not in use.