I currently have a 5x2ft tank. My realistic dream tank would an 8x4 or 10x5 peninsula that I don’t have room for (could make room, but nothing in an ideal area that can be plumbed to another room).
I may think about upgrading to a 6x3 peninsula in the next couple of years depending how my current new tank grows out.
I designed in my mind my dream tank. It would be best described as 4 rectangle tanks connected. So, like a donut, but square. The length of each “tank/side” would have to be at least 6 feet, to accommodate the interior view of the tank and for aesthetics would be where you access the multiple sumps under each side.
The fish could then swim around and around. I would want one “side” to be a drop off. So, I would at least want an 8 foot tank for each side, thus the drop off side would be 8 wide X 5’ deep/tall X hmm, 3 foot front to back.
There would be an access door under one side, so the sump there would be smaller.
I would like one side to be mostly sand and gorgonians, sea fans, etc. And, the drop off side would have a 5’ deep rock wall.