Angled Heaters

[Mr Tomato]

Here’s an interesting thought..’Aquarium heaters; they often tell you to place heaters at an angle at the rear of the tank. Many years ago, I began experimenting with new ideas. I never liked the heater in the angled position. It looked odd to me, stuck there in an untidy way. I found it almost impossible to hide it with rocks-plants, ect, and it made cleaning the back glass so awkward too.
I decided to place the heater in the corner straight up the corner. Then, worried about the heater malfunctioning as suggested in the instructions, I turned the power head so that the flow was directed at the heater. It worked. As the heater came on, and even flow carried the heated water straight off, and it showed no signs of breaking down, no signs of temperature fluxuation and that heater, old it may be but still works today!
And by placing a plant in front of it, the nasty ugly heater was easily blended into vanish-land.
Hope this helps..he said.

 

[winkle]

I've got my heater stood upright, next to my filter... both of which are obscured by the bubble curtain from an airstone. When the heater comes on, I can see the shimmery heat from the heater being dragged downwards towards the airstone and then it gets pulled up by the airstone bubbles. It keeps the heater well hidden and the water well mixed.

 

[OldMan47]

My own heaters are at almost any angle. I figure that a heater getting good flow will respond correctly regardless of the angle. My tank temperatures are fairly stable so I see no reason to worry about the angle. As it turns out, my heated tanks often have heaters that are nearly horizontal near the bottom of my tanks. That makes them easy to hide from a tank's front view.

 

[dtw]

I think they just state 'at an angle' so you can still get at the temperature dial but also not having the tube vertical as the heating elements are obviously longer than wider and will spread heat better the more horizontal they are.
But like you've said, with sufficient flow the tube won't get a hot spot and the heat will spead out evenly in the tank anyway.
The instructions are probably aimed more at tanks with little or no flow of water, but with most tanks being wider than they are high, middle at the back and horizontal or angled is going to be best generally.