Heater wattage?

[Newbs64]

Getting ready to order the cobalt heater and they have different watts. I read a article that you 5 watts per gallon. I wanted you guy's opinion! I just bought a 20 gallon long, so if what I read was true I need a 100watt. What do you think?

 

[Newbs64]

6 views and no replies? Is this a stupid question or?

 

[ErinCahir]

5 watts per gallon is the rule of thumb, yes.

 

[Newbs64]

5 watts per gallon is the rule of thumb, yes.

Thank you.