This is some more Ideas that I used on my 125 stand. I finished it about 1 year ago and I think I got it the way I wanted it. The main thing was not to rush it. I’m not an expert but I sent a lot of time on mine. I hope this will help. I have had a salt tank or 5 for 25 years and I learn new things all the time. When I built my stand I made it 40" tall so I had plenty of room down under for skimmer. I made the stand just a little bigger than the tank (½”) so the outside of the tank sits on the top of the 2x4s and it made it easier to use my reef ready pluming. The feed throws are hard to put on with a solid wood top on the stand. As for the bottom I coated it with truck bed liner coating from auto parts store so it holds water. My pumps are mounted on adjustable shelves mounted on the back witch mad it easy when it came to power strips and timer, 6” shelves. I have my tank is about 10”s from the wall for back entry or work from the back. I’m working on the pics. Sorry so long winded. Good luck and have fun with it.
Scott