Are you using Purigen in this system?
This sump is clean, you've come a long way my friend.
Yeah but not sure how well it will work
Thanks man. Owe it to guys like you that answered all my dumb questions.
I would consider lowering the water level a little bit or repoisitioning the media. I'd want the water to have a more direct route across the media. Looks like you've got several inches of water above the media.

Just get a cheap power head and put that in the sump. Water movement in the sump is good. Keeps water moving around the bio-media, too. When I set my sump up, the water was just too calm, so I put power heads in my sump.
Keeps my rubber ducky from getting scummy, too.
You do have a rubber ducky in that sump, right? GOT to have that, for sure.