hello i have a dual temp heater that came with my tank and i was jw the best place/way to put it in the tank. i noticed in some pics ppl have thiers on an angle. also is it ok if it is totally submerged in the water?
I personally think it best to have it lying horizontal near the bottom rather than vertical because its more efficient that way because cold water sinks to the bottom.
make sure it's a submersible heater though , if it has a hook where it sits over the edge of the tank...don't submerge it! You could get horribly shocked.