Rusty, I wouldn't have anything that eats algae in the refugium. It defeats the purpose.
Mine is also simple, but a big larger.
It started out like this-
The shallow 50 gallon stock tank holds algae and some live rock, and drains into the 100 gallon stock tank on the floor that has another 60 or so pounds of live rock in it.
Then I went to two 50 gallon stock tanks, I added the filter socks, and a second skimmer. There is another 50 pounds of rock in the second shallow tank. They still drain into the 100 gallon tank on the floor.