Here is my thoughts on my Fluval E300 Digital Aquarium heater.
Author: Dos Format
they are built mainly for a marine tank as need alot of flow so waavemakes in the tank they work spot on in mine get a small wavemaker pointed at it workes baeltin no mater how you mount it
The heater in the aquarium is a 300w unit
I have a 300 works great and it up write no issu