What to add to sump??

Hello.
New setup.
Right now I've got a Megaflow Model 1 sump going because its about the only one that I could find that fits in my tight cabinet space.
I've got about 10 lbs LR rubble, a Coralife SS 125, an eheim 1262 return, and an auto top off. I had hopes of modding it into a refugium type setup but it seems with all that crap there just isn't enough space in this sump to house one. Is this good enough for a 54g reef tank? Sure I could stuff a light in there and try to grow some macro, but anyone know of some better uses for this setup?

 

looks like you have space for macro over the rocks, that is pretty much what I do

 

Looks good to me unless you want to start thinking about controllers, maybe automated dosing etc although with your tight space it might be limiting. You could consider running carbon (GAC) although it's by no means necessary, it might be worth researching.

 

I'd say a bag of carbon