All of that looks great!! Very clean and organized. It looks like an extension of the stand in the last picture!Here is my electrical board, inspired by week 6 of Bulk Reef Supply's 52 Weeks of Reefing video. I decided to put the electrical board next to the tank rather than underneath to keep it farther from saltwater, improve access, and leave room for the ATO reservoir under the tank.
Front of the electrical board. The ATO controller will be placed in the upper left position. Power strip is a Kill-A-Watt.
Back of the electrical board. Transformers are attached to the plywood with Velcro. Wires are organized with twisty ties and these Velcro wire ties, which I screwed to the plywood. The outlet box at lower left allows one heater controller (top center on front side) to be the redundant high-temperature cutoff for two heaters in the sump.
Black Krylon paint over hardwood veneer plywood left over from another project provides a good color match to my Reefer 250 cabinet.