If one sump is good...

The 20 gal tank I had planned to use for mys sump will indeed fit under my stand. Unfortunately, there is no way to get it in there. I can slide it vertically through one of the stand doors but there isn't room to tilt it down into position.

Plan B
I need to do this as inexpensively as possible so I'm not buy a pre-made acrylic sump nor am I going to take the time to custom make an acrylic sump that will just fit into the stand. The largest tank I can place into the stand turns out to be 10 gallons. I feel that a 10 gallon tank is too small. Once I add the deep sand bed and allow room for the water to rise in a power failure there won't be enough water volume in the tank. So, I'll use two tanks. It so happens that I have two of these already.

I will connect the two tanks together with PVC plumbing and bulkheads to allow the water to flow between them. One tank will have a deep sand bed and will serve as the refugium. The other tank will house the protein skimmer, sump and return pump. Water from my overflow box will flow into both tanks and I'll use valves to set the flow through the refugium. The output of the refugium will flow into the chamber that houses the protein skimmer in the second tank. A baffle will set the water level for the protein skimmer and refugium. Water from the overflow box that didn't go directly into the refugium will flow into the skimmer chamber. A set of baffles will eliminate bubbles as the water flows into the sump that houses the return pump. I'm also going to add a Durso Standpipe to my overflow box to cut down on noise. I am also going to add a float valve in the sump to handle automatic top offs. I'll post a set of plans soon and pictures when I complete it.

I can't wait to get started on this. My nitrates are still high and I need to do something soon. I'm losing my tongue coral. My glass hole saw and bulkheads are on order from glass-holes.com. Creative name, huh?