So I had to move to IL for work which forced me to tear down my 120gallon display. I had a basement sump with a large refugium tank and water storage. I had a great setup and the tank did really well. It was sad to tear it all out but it had to go when I got the word I was moving. I did not think I could get setup again for years but it seems that has changed. I had a thread called "My wife just awakened a monster". I wanted main floor displays with sumps in the basement but the wife said no holes in the floor. I argued for months and lost. Unfortunately for my wife I asked what can I do in the basement and she said "I don't care what you do". This awakened the monster. At first I was not sure what to do as I had a limited size glass tank I could fit down the stairs. After some research I decided plywood was going to be the material of choice for these tanks as I could fit it in the basement and assemble it on my own. I have made some progress after I finalized the plans. I always wanted a split system. As much as I love having a reef tank there are still many fish I always wanted to keep that are not reef safe. I had the idea of a massive drop off tank that was 96" x 96" with the shallow end and 24" and the deep end at 48". After thinking about this a lot I scrapped the idea in part because a tank with that size would not be practical for access and fish separation. Also going over 36" deep brings in another list of issues to deal with. I was going to stagger the two tanks as the next idea but then the space was limited for viewing the reef tank and then the wife suggested side by side. I have moved forward with the side by side idea with the two tanks being tied into one system. The big question was how big can I go and feel confident about the construction and materials I plan to use. I found out that a 4'x8' sheet of plywood fits in the basement so that was the deciding factor for the bottom LxW size. As for height that was an easy choice on the reef tank 24" tall. The fish tank side will go 36" tall as that is a safe height for 3/4" glass. So the reef tank size is 96"L x 48"W x 24"T ~480 gallons. The fish tank is going to be 96"L x 48"W x 36"T ~720 gallons. I like tanks lower to the floor so the reef tanks stand is ~30" tall and the fish tank stand is only ~18" tall. I plan to use 3/4" Starphire glass for both tank viewing panels. Both tanks with overflow into a single 3 stage sump. Stage 1 120gallon tank with skimmers. Stage 2 Refugium 90-120 gallons in size. Stage 3 200-300 gallons: heating, dosing, top off, return. Tank construction 3/4" Birch plywood. Secured using 2" anti-corrosion deck screws and water resistant wood glue. Plywood will be doubled up with screws and glue for all seams. Epoxy and fiberglass will be used to waterproof the interior of both tanks. Stand construction 2x4s framed together with distributed support. There will be no under tank filtration so the there are 48 support legs spread out across each stand. Plans Reef tank will have sand 1-2" of sand and the fish tank will be bare bottom with a HDPE sheet attached to the bottom. Water storage planned RODI: 200 gallons freshwater and 200 gallons saltwater. Lighting plans LEDs for both tanks. Manufacturer TBD. Power 2 20amp circuits dedicated to the aquariums. Backup tri-fuel generator to be installed TBD. Quarantine System TBD. Ventilation fans with humidistat to be installed for humidity control. Insulation for the fish room will also be completed to prevent unwanted humidity damage to the house. Water flow TBD Return pump 1 or 2 Reeflo Hammerheads. Access to tanks will be via doors in front of both tanks and a raised platform behind both tanks. Unanswered questions. Top Bracing for both tanks is still under consideration. Per plans I have seen online at least 1 brace is needed on the 24" deep tank. The 36" deep tank I plan at least 2 braces across the tank. Both tanks will have a rim brace minimum 3" around the entire top. More research and input is needed to determine the bracing requirements. Suggestions are welcome. Foam for the tank bottoms. As both tanks are flat bottom and wood is never perfectly flat I plan to use foam between the stand and display tanks. Still need ideas for this foam IE: thickness and type. Suggestions are welcome. Lets not forget some pictures. I will add more as there is more progress. This build is going to take a while.