$.02 on two filters:
I have been running an Emperor 280 for a few years and currently it is on a FW
20L lightly planted with only 5 golden tetras (am planning to increase the population). Sturdy and reliable and have only cleaned the impeller housing a few times. Biowheel has never been a problem. Cost of the cartridges is adding up though (thought of using a custom reusable sponge instead). Not heavy into plants so I am not worried about CO2
loss. Motor produces a noticeable hum. Splashing sound is dependent on the water level.
Just bought an Aquaclear 50 on sale and hooked it up to the same tank for comparison. Much smaller in size (pumps 200 gph
as opposed to 280 gph
). I like the flexible media options. Motor runs silent!!! The water exit lip is rather high so there is a splashing sound and the water re-enters the tank at 45 degrees rather than across the surface. In the past I have made "lip extenders" out of the plastic strip that comes with hinged glass tops to direct the flow and eliminate splash. Involves some cutting, heating, and bending. Filter intake slots are larger so that may be a concern with smaller tank inhabitants.
Once the AC50 gets properly seeded I might shutoff the Emperor. Mostly for the noise. Plus, 480 combined gph
for a 20L is a bit much IMO
. Fish are getting their exercise
Best of luck.