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##### Asked by: Invencion Evranov

pets fish and aquariums# How many watts does an aquarium heater use per gallon?

In this regard, how many watts do I need for my aquarium heater?

Most **aquarium heaters** range from 25 **watts** to 300 **watts**. Smaller **aquariums** require smaller **heaters**. A 10-gallon tank, for example, will typically **need** a 25- to 75-**watt heater**, while a 75-gallon tank will require 250 to 300 **watts**. Larger tanks may require multiple **heaters**.

**heaters**are pretty reliable (as long as you stick with the well-established brands) and a 50W shouldn't generate too much

**heat**too quickly for a

**2.5**-

**gallon**.

Likewise, will a 50 watt heater work for a 20 gallon tank?

Yes you **can** have a **50 watt heater** in a **20 gallon**. Another thing is since a betta **tank** should be kept at 78-80 you might overwork the **heater**. Normally larger is better so that you don't over **work** the **heater**.

A **40 gallon** fish **tank** will need at least a 120-**watt** heater if the room it is kept in is 5 degrees cooler than your aquarium. If the room is 10 degrees cooler then a **40 gallon tank** will need a 200-**watt** heater.