Very few tanks like this and have a few questions as I am planning two that are almost the exact same type of setup.
I have a fishroom that will house all the stuff on the opposite side of the wall like yours. One tank is going above the toilet lol, and the other in a hallway. I wanted to put the one in the bathroom inside the shower with lights peeking through a tile like shadow box but the people that put the tile in the shower were very concerned with the water proofing system they used (schluter system with a seal for the lighting) so decided against it.
I'm curious to the actual iron framing/plate you used. I'm picturing it as just a plate with like L brackets for the screws. I have 16" on center framing and am a little concerned that I may need to open up the wall to add some more nailer studs but not sure if will really need more than three screws holding it to the wall.
I am worried a little about once its screwed to the studs that when the water is added that it will compress the drywall and cause it to lean down. Did you cut a slit in the drywall for the plate? That seems like the easiest thing to do, just cut a strip of the drywall away where the plate will be snug up against the studs.
Any advice/details of how you attatched the plate would be great.