Hi there,

Was just wandering why some people put there heaters diagonal across their tank? The instructions on my heater advise to put it vertical.

Hi there,

Was just wandering why some people put there heaters diagonal across their tank? The instructions on my heater advise to put it vertical.

Horizontal is better because you can put it lower so it doesn't come out of the water during water changes and gives microscopically better heat regulation.

Also if it's a long heater it can fit better than vertical.

In the case of my tank it's diagonal because the cord isn't long enough to have it low in the tank and horizontal.

Tank not deep enough?

There is the suggestion that with the heater at the bottom and the thermostat at the top, you get a false reading of temp as the hot water around the heater rises and the thermostat thinks the overall water temp is higher than it is so switches the heater off. If you angle the heaterstat this problem is alleviated.

My vertically placed heaters are in the path of the filter output. Where I don't have a current running, I have positioned the heater diagonally.

Thanks for the suggestions everyone

i have mine horozontal at the bottom, close to the gravel so i can hide it easily and make the tank less ugly

mine is diagonal as i lost the suction cup :facepalm:

Not many heater/thermostats are actually guaranteed to operate completely submersed and should have the cap out of the water. Even the better brands will often end up with water inside. This could be a good reason to keep them verticle. Water inside can cause corrosion and well the points together which will give you cooked fish. Water inside can also trip the overloads on your electrical system--a problem I had recently.

I dont think it really matters how you put you heater in the tank. Just make sure it has little water flow around it and is not touching any substrate.

i have mine vertical and horizontal and they all keep the tank at the correct temp so I see no advantage with it being horizontal over vertical. the one I have horizontal is that way because it is over 500mm long and the tank in only 450mm tall.

i have mine vertical and horizontal and they all keep the tank at the correct temp so I see no advantage with it being horizontal over vertical. the one I have horizontal is that way because it is over 500mm long and the tank in only 450mm tall.

Yeah i think that is the main reason why you see them on the horizontal. To fit them in the tanks.

That makes sense. So I should put my heater by the filter outlet?

That makes sense. So I should put my heater by the filter outlet?

you can but not needed if you have a good circulation in the tank.

I have it right next to filter intake at the mo

I have it right next to filter intake at the mo

i suppose in theory that the heater will potentially be heating water that goes into the filter and if it is an external some of that heat will be lost but i doubt it will be of any significance at all. if it is keeping the tank at the desired temp it's fine.