Touring Mark's Ultimate 12-Foot Step-Down Aquarium! | Mark Callahan, Mr. Saltwater Tank

06-25-2026 In this highly anticipated, part-one episode, Jimmy finally calls out Mark (Mr. Saltwater Tank) to give an exclusive, long-overdue tour of his massive, custom 12-foot Planet Aquariums step-down peninsula reef tank. Built on the second story of a custom home addition, Mark breaks down the insane logistics of building this monster aquarium, structurally reinforcing the floor with steel, and literally craning the massive tank and stand through a second-story window. Discover how he manages and services the unique 4-foot deep drop-off section, the engineering behind the plumbing to the downstairs fish room, and the inspiration behind the real reef rock aquascape, drawing from real-world diving experiences in Vanuatu, Okinawa, and Australia. Whether you are a seasoned reef junkie or just love mind-blowing custom aquarium builds, this behind-the-scenes look at one of the ultimate home reef tanks is a must-watch! ______________________________________________ ⚠️ Products In This Video ► Real Reef Rock Large 8-16" (by the pound) - https://www.saltwateraquarium.com/rea... ► Real Reef FANCY Branch Rock (by the lb) Box - https://www.saltwateraquarium.com/rea... ► Real Reef Turbinaria Cup Plate Coral Rock (1 pc) - https://www.saltwateraquarium.com/rea... ► (Single FANCY Arch) Real Reef Arches - https://www.saltwateraquarium.com/sin... ► Tunze 33.86" Aquarium Foldable Tongs Carbon Fiber (33.86") 0220.450 - https://www.saltwateraquarium.com/33-... ► Tunze 33.86" Aquarium Foldable Anodized Aluminum Tongs 0220.440 - https://www.saltwateraquarium.com/33-... ► ORA Aquacultured Micronesian Lobophyllia Coral - https://www.saltwateraquarium.com/aqu... ► ORA Aquacultured Purple and Green Ricordea Yuma Coral (Ricordea yuma) - https://www.saltwateraquarium.com/aqu... ► St. Thomas Mushroom - https://www.saltwateraquarium.com/st-... ► Purple Mummy Eye Chalice Coral - https://www.saltwateraquarium.com/pur... ______________________________________________ Website - https://www.saltwateraquarium.com Follow us on Facebook -   / swaqdotcom   Follow us on Instagram -   / saltwateraquariumdotcom   Follow us on TikTok -   / saltwateraquarium.com   ______________________________________________ 📩 If you have a request related to equipment in this video, or this video in general, email - [email protected] #saltwateraquarium #swaq