What size heater for a220ltr marine reef/fish tank?
You want to have about 3-5 watts per gallon in most instances, so a 220 liter would be about 160 gallons. That would require 480W-800W. For tanks over 30 gallons, I recommend having 2 heaters of the same wattage, one on each end of the tank. This gives you more even heating plus an emergency backup since heaters will eventually burn out. So I would suggest purchasing another 300W for a total of 600W, which would put you within the rec commended range. The exception here would be if you needed to heat your tank more than 10 degrees (Fahrenheit) over your room temperature – then you’d want to increase the wattage (for both heaters).
