300 Watt Heater OK in 29 Gallon Tank?

My 150 watt Aqueon Pro heater recently developed an issue where the LED heating indicator would flicker instead of staying lit a solid red when in heating mode. I am not sure if that change in behavior is an indication of an issue with the heater. It has been been in use for 71/2 years, and it is still maintaining the tank at 78 degrees Fahrenheit. I unplugged it, and put in a Marineland VisI Therm 300 watt heater in its place until I sort out the Aqueon Pro heater.

Is the 300 watt heater going to be a problem in this size tank? During the winter months the temperature in the room where the aquarium is located can get down to 62 to 65 degrees Fahrenheit at night. The rest of the year, the differential between the tank temperature and room temperature is not as much, and in the summer the room can be more than tank heater setting of 78 degrees, unless the air conditioning is running. The VisI Therm is probably 5 to 7 years old, too. It was purchased and never used until now. It seems to be working fine as a replacement. Would it be OK just to leave the 300 watt VisI Therm heater in the tank permanently?

 

Using an overpowered heater is not ideal. Every heater has a small temperature difference between it's on and off temperatures this is needed to prevent the thermostats from flicking on and off too often when it reaches temperature. Usually a new heater has only a small difference in temperature but as they age the gap often gets bigger. If a heater is too powerful for the tank when it comes on it warms the water quickly and many fish don't like the sudden rise. If you have a room that sometimes gets colder I would use an appropriately sized heater with a second small heater set slightly lower to kick in if the main heater can't keep the temperature up.

 

Yes that will be fine in your 29 gallon.

 

As long as it doesn’t get stuck on. If it does it will heat that water rapidly.

 

I had the 150 watt Aqueon Pro heater powered off for two days. I powered it back on, and so fat it has worked properly - no more flickering of the LED when in heat mode. This heater has been in service for 7.5 years. Is it at the end of its life?