Adding refugium to sump

[HarleyC]

Hi Guys,
Have the new tank all set up now and it's loooking good - will post pics later.
First tests yesterday were fairly decent (DKH 9, Nitrate 25, Phosphate 0.05, Calcium 400, Magnesium 1.350) apart from Nitrate around 25, which is to be expected initially, correct?
This was a 4 year established tank that we moved.

Big shout out to Raf and Diana at Aquatic escapes and Burgerchow (seller) for their help!

Anyway, I have the 3', 50G sump, but there isn't a dedicated refugium portion. At this point I don't want to empty it all and add a glass partition etc.
Any ideas for drop in refugiums and what works best? - I currently have about 10 x 10 inches of space I could utilize. Or, 10x16" if the return pipes can feed in to the refugium?

Thanks in advance for the help.
Harley