Here is a really good sump design that I know works and works well.
Description: Water from the overflow comes in on the left side of the tank. The protein skimmer can skim as much as it can and then the Under Over Under design eliminates most microbubbles, not the over under over design that you have in your sump. The water then flows to your return pump bubble free. The union (the orange thing) will let you take off your return pump to do maintenance or allow you to replace it if necessary. At the top of the pipe, you will see a red diagonal line, this is a ball valve. It may be needed to control your return pumps flow rate. It's not entirely necessary at all, but I go valve crazy when I set up new systems because I like mass customization. Anyways, the split off your main return line plumbing feeds a "relief valve" that puts some of the return pumps water back into the fuge section of your sump. Doing it this way will keep a constant water level in your fuge, and nothing will dry out if you don't add top off for a few days. The water then flows from the fuge, over the rim of the glass and into another Under Over Under baffle design that will eliminates any microbubbles from entering your return pump. This is also a very quiet sump design, where you can add blue and white filter floss between the fuge glass and the first baffle to eliminate algae from getting sucked into your return pump.
This sump also allows you to have some pretty good customization because that return pump relief valve that controls the flow in the refugium can be turned into an algae scrubber at a later time or even able to power a few other pieces of equipment (with the right size return pump of course!)
Anyways, I hope this helps. This is the way I would do it if I were you.
Just wanted to have the last word. lol!!!
