While I had a perfectly good stand from the previous setup it wasn't going to work for the new setup. So, back to the drawing board. The stand is 24" deep, 18" wide, 35" high to the tank platform, and 54.5" high in the back section. Making the stand 24" deep allowed me to fit a standard 10g tank in the stand to use a sump as well as 6" behind the aquarium to hide all the plumbing and external overflow box.
The frame uses 1x3s for the vertical supports and 1x6s for the horizontal frame. I went with the thicker 1x6s to increase stability, using 1x3s made it difficult to keep square and I worried long term it might list to one side.
The side and back of the stand is skinned with 1/4" plywood while the front is 1/2" plywood. I cut a window in the door to display the planted refugium.
Besides the front door, there will be an access hatch on the top of the back section and the top half of the back panel is removable in case major renovations are in order and I don't want to move and/or completely drain the tank.
Originally I had intended for there to be a canopy but it was proving too difficult to line up with both the stand and the aquarium so in the interest of completing the project I cut the top off. There will be more light spill and evaporation but I'll survive.
I finished staining the stand today, went with a natural finish stain. I am hoping to start applying poly coats tomorrow.