One heater or two???

[Guppygirl]

I have a 20 gallon long tank, that is ready to be set up. I have never had a 20 this long before, my other 2 I own are the normal sized ones. I am upgrading from many 10 gallons so I have a few extra 50watt heaters. My other 15 and 20 have 100 watt heaters. So now I am wondering if I should put one 100 watt heater in the 20 long or 2 50 watt heaters or should it be 2 100 watt heaters? Any ideas would be helpful. :bow: The tank is to house my bronze and peppered cories and my new albino bristlenose and maybe some guppies? :thumbs:

[jvision]

It really depends on what your room temp is like. When I lived in an apartment (and the tanks we keep at work), the room was warm enough that I didn't need heaters. WHen I lived in an old house that was drafty and had wild temp. swings, I used 2 heaters each rated for the full tank size (ie. 2 100W heaters for a 20gal). In my house now, the temp is fairly constant, and if the heater failed, the fish would be cool but not dead, so I just use one heater.

[phoenixn7g]

I have a 20 gallon long tank, that is ready to be set up. I have never had a 20 this long before, my other 2 I own are the normal sized ones. I am upgrading from many 10 gallons so I have a few extra 50watt heaters. My other 15 and 20 have 100 watt heaters. So now I am wondering if I should put one 100 watt heater in the 20 long or 2 50 watt heaters or should it be 2 100 watt heaters? Any ideas would be helpful. :bow: The tank is to house my bronze and peppered cories and my new albino bristlenose and maybe some guppies? :thumbs:

Rule of Thumb IMO is 5 wpg. So 5 watts * 20 gallons= 100 watts. If you are really that concerned do 2 50 watts, but I think one 100 watt will be fine unless the tank is like 4 feet long.