South Shields here
Im pretty jelly of the separate fuge, mines in the sump. If it were me i might have a mangrove in there (always wanted one)
Not sure if im allowed to mention names but i use charterhouse aquatics and kraken corals for all my equipment needs (both uk) next day delivery. They also sell any fittings you may need and are able to suggest the right parts for the job.
The fuge will help with cycling, it will act as a food source for copepods and other beneficial organisms.
Welcome to r2r! Love the biorb refugium idea! Very cool. You should start a build thread for this setup so we can follow along with the journey. Also don’t hesitate to ask any questions you may (will) have, we love to help ;-)
Welcome Phoebe! As many have already shared their admiration and affection for your bio orb refuge, I shall too. That orb is awesome! The rest of your system looks and sounds amazing too. Best of luck!