How do you determine heater wattage?

I'm looking to get a heater for my aquarium as mine burned up a few weeks ago. The water temperature maintained a pretty constant temperature but since it is getting cooler here, it is starting to fluctuate. Can someone tell me how to determine the wattage needed for my 55g aquarium?

Heater recommendations are also appreciated.

 

150w would be the lowest to go. 200w would be acceptable and 300w would be more than sufficient

 

5 - 7 watts per gallon is a general principle depending on ambient temp of locality ( what the water temp would be if no heater was used)

types - for a Reef tank with valuable stock a Titanium heater is a good investment if its going to be working often ( in my climate any old throwaway is OK as its only on for 1 month per year other than that chiller controls the tank temp)

on the normals types - good brands IME are Rena, Visitherm and others I cant recall now

2 heaters would be better than 1 - so 2 x 150 watt may be ideal for you

reason - 1 heater may fail and if its stuck in the on position then your water gets to hot to soon if it was 300 watt and if its sticks in the off position then your water cools to ambient temp which in winter means you need to go out and buy one quickly

so running 2 small ones or having a spare in the cabinet is ideal IME

Steve

 

Heater Notes

These notes might help you.

Mark

 

The heaters usually tell you what amount of water they can raise a given number of degrees above the ambient temperature. When you find one that will get you the desired move, I would go one size smaller and grab two of them, since heaters are by far the things that break down most often on tanks.