Very simple sump system?

So I have a new 55 gallon freshwater planted tank and was thinking of
setting up a very simple sump sytem.

My goals are to:

Simplify water changes or water addition
Simplify dosing of chemicals or medications
Move unsightly heaters and air bubbles from main tank
Increase oxygenation by heavily aerating sump
Keep CO2 generation out of main tank


I drew a diagram for the idea I have - http://jonnythan.com/sump.gif

I was planning on drilling a small hole at the top of the tank and running a
tube down into the sump (10 gallon?) tank. Use my Eheim Ecco filter as a
pump to remove water from the sump and pump it into the main tank.

I was also planning on putting a Fluval internal filter into the main tank
for some additional mechanical filtration and to have something that's still
running during filter maintenance.

Anyone have any comments or suggestions on this setup? Thanks.

Jon