a 100watt heater is overkill for a 40 ltr tank. If the heater ever got stuck in the on position, I'd say you'll have a boiling tank.
Is the heater on a vertical position? If it isn't, try that.
But might pay to buy a 50watt heater
opps, Sorry, I did not mean to say that mods are full of innuendo. I was meaning that that thread was full of it.
Yeah, I object to mods being called nazis too. too much dead and destruction relating to WWII and Nazis to use it in any form of joke.