Proper Heater Sizing by Ardan Huck

[FishLover]

Here is something I found from the web
Proper Heater Sizing
Ardan Huck March 15, 2003


Choosing the proper heater size is important to maintain constant temperatures and to be able to raise the temperature high enough to treat certain diseases.

The size of the heater required depends on:

1. Size of the tank
2. Temperature of the air in the room surrounding the tank
3. Other factors may include air movement, filters, covers, and lights

A general rule is to have three to five watts per gallon for every 10? Fahrenheit above room temperature that you wish to have the water temperature.


Example:
Room temperature = 68? F
Aquarium temperature desired = 88? F
50 gallon tank

Formula = Difference between room temperature and desired tank temperature is 20? F (two times the 10? difference)

3 watts X 50 gallons X 2 = 300 watts "minimum" (a larger heater may be desired for raising the temperature for disease treatments)

[RichVic]

Hi there
Do you know how many litres are in one US Gallon?
I always thought that if you had a 100lt tank you needed a minimum 100w
heater? Very simple - but how does that compare?

[Proteus]

3.8L to the gallon

i.e. 50g = 190L

Personally I disagree with the calculations mntioned in the original post. A 200w or 250w heater would be sufficient, or, even a 150w Jager would easily deal with that volume of water based on the size of the heater.

[samir]

i use a 300 wat for a 250 litre and it keeps the temp around 30c.
here's an online calculator thats pretty decent
http://boonedocks.net/fishtank/ftweb.php

[FishLover]

You really have to factor in the difference between Room temperature and Aquarium temperature desired. If the difference is not much, then you can use a smaller heater. Otherwise, you will have a tough time keeping the tank temp.