You now have a compartment for heater, skimmer, and water inlet. A compartment for refugium. And a compartment for return water.
You need all 3 .... you dont was your pump to be sucking up pods, snails, crabs, sand , ect and you dont want to refugium stired up from rushing water , thats why the gravity feed (trap style supply) from inlet compartment to the refugium is a good way of doing it. and the water fall technique from refugium to return pump keeps the flow in the refugium going.
Top view of finished product you can see the mag7 sitting solo in the return area, and the skimmer , heater , and 1" pvp inlet on the opposite side.
Your going to want to wait a day to let the silicone cure. there wont be a lot of pressure but you want to make sure you go around the dividers well with the silicone. and any messes can be cleaned up from the glass with a razor blade.