Heater for 20 gallon high

Dillan Murphy

Member
Is 200 watts to much for a 20 gallon high, is a 155 watt more suitable?
 

MacZ

Member
I got a 100 watts in a 20 and used a 75 watts before. It depends more on the room temperature. The warmer the room, the less watts you actually need. But always go by the coldest possible room temp.
 
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Dillan Murphy

Member
I keep my house at about 70 degrees
 

MacZ

Member
That's about 20 in Celsius, right? Then a 75-100 watt heater is enough.
 

RayClem

Member
For a 20 gallon tank, recommendations include anything between 50 watts to 150 watts depending upon the required temperature rise. If you are keeping the tank at a typical community aquarium temperature of 78 degrees F and your MINIMUM house temperature is 70 degrees, a 75-100 watt heater should be adequate.

If your house temperature dips at night in the winter to save heating costs, then you might need a 150 watt heater. The disadvantage of purchasing a heater that is too large for the aquarium is that the thermostat can stick causing the water to become excessively hot, killing your fish. Unfortunately, another recent post confirms this reality.

When purchasing a heater, it is best to purchase a backup heater as well. Eventually, heaters do fail. Thus, having a spare to protect your investment in fish is a good thing.
 
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Dillan Murphy

Member
I'm looking at a heater on Amazon that is 100 watts it says its for a 6.5 to 13 gallon tank will it still work.
 

Pfrozen

Member
im using a 100w heater... i always thought the rule of thumb was gallon times five... so 50w for a 10g, 100w for a 20g, etc
 

RayClem

Member
Dillan Murphy said:
I'm looking at a heater on Amazon that is 100 watts it says its for a 6.5 to 13 gallon tank will it still work.
Pfrozen said:
im using a 100w heater... i always thought the rule of thumb was gallon times five... so 50w for a 10g, 100w for a 20g, etc

The rule of thumb is based on "typical" room temperatures and "typical" tank temperatures. However, it is best to look at specific circumstances.

For the 70 degree room temperature noted, a 100 watt heater should have no issue heating a 20 gallon tank to 78 degrees. If you wanted to keep the tank warmer than that, or if your room gets cooler than 70 degrees at night, then you might want a use 150 watts, but 100 watts should be sufficient based on the situation posed.

I have a couple of 20 gallon tanks in my basement. It can get down to 60-65 degrees F in the winter, especially if there is a Polar Vortex dropping the outside temperatures to bitterly cold levels. Thus, a 100 watt heater would not be sufficient for them. In that situation, the "rule of thumb" would not work.
 
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