01-24-2005, 12:37 PM
Join Date: Mar 2004
Location: Plano, TX
iTrader Positive Rating: 100%
I have seen tables in the past and they usually not reliable. To size a heater one would determine how many degrees above ambient is required.
From Aquatic EcoSystems (bold is my own)
For every 9°F (5°C) difference, there should be 4W of heat per gallon (3.8 liters) of water. Elevated, non-insulated tanks, with a large amount of surface agitation, could require as much as 12W per gallon per 9°F. For small glass aquaria, use 8W per gallon per 9°F.