Since I finally have my new system filled with water, and am doing some testing on the plumbing, I thought I would show some progress. I'll start from the beginning. I purchased the tank used from Aquarium Obsessed some time last year. I believe it was Will's (from AO) tank that he kept at the AO office. The tank measures 74"x48"x32" all 19mm glass with the two long and one short panel starphire glass. The tank was completely disassembled and resealed prior to being sold. Since the tank was being rebuilt, I made some changes regarding the location of the overlow. The DT is kept in its own room on the main level of my house, and an equipment room is directly below it in the basement. The location in my house is not perfect for this tank, but I wanted it anyways. Matter of fact, the awkwardness of working on a tank this large may finally drive me out of the hobby for good. Anyways this is where the DT will be located. Steel stand in place. I construced an equipment room below the DT to house the sump, and all other supporting equipment. There are four posts, and a couple of laminated beams placed directly below the DT for support. The final support is framed up more than what is pictured, but this gives the basic idea. Tank was delivered some time this past summer, and sat in my garage while I figured how I was going to get this thing into my house. There was no way to pick this tank up, and manage to get through doorways, so we used a small telehandler to reach it into the house. It ended up on some carts, wheeled into position, and lifted up with some jacks. A couple hundred pounds of Pukani base rock were strung up with acrylic rods and base plates to support the structures. The black duct above the tank was installed and runs directly to an HRV for humidity control (equipment room is also ducted to the HRV). A shallow sand bed was also added, probably about 300 pounds. Plumbing from the overflow to the basement. The left is the return. The main siphon line (beananimal type) from the overflow goes directly into a three way valve. The valve controls the direction of the flow to either enter a 175 gallon tank, or go directly to the sump. The purpose of the tank is to create an easier way to do water changes, and also add more water volume to the system. By directing the flow directly to the sump, I can isolate the holding tank from the system without interuption. Once isolated, the tank can be drained, filled with RO from the tank on the right side, add salt, mixed with the inline pump, and added back to the system.