Refugium in aquaone reefsys 180

[Zoanthusprime]

Hi all,
Im running my 180L aquaone reefsys that i got second hand. Not looking to upgrade as of yet but curious if anyone has managed to fit a refugium in the sump. Should I be looking into reactors instead? Just dont seem to have the room in my sump with the skimmer and too scared to do any drastic changes.

Attatched is a photo of my sump

 

[Rocks reef]

Not much room in there by the looks of it, I'd run a reactor or two if that is what you are wanting.