Here's my cheap, but effective DIY project. I have this on my 75 gallon freshwater tank. Go to WalMart and get one of those plastic stackable storage drawer sets for about $8.00. You can use either two drawers or three drawers depending on how much room you have to work with.

Your overflow box drains directly into the top drawer. Using 3 drawers, drill holes in the bottom of the first two drawers to create the trickle effect. Fill the second drawer with bio balls or whatever bio media you plan to use. The third drawer can drain into your sump to be returned to the tank. I think the best is the 3 drawer setup. My bio media drawer fills with water sometime because it doesn't drain fast enough. I should have drilled holes in it and used a 3rd drawer. I used plastic pot scrubbers from the dollar store instead of bio balls.