I just spent way too long doing a rip-clean for my GHA issue and at this point I am wishing the 120 was shallower.
If you do go bigger, stay shallow because it eases maintenance. Also, it may not be as much of a difference going from 2 tanks to one bigger tank.
A 4x2x2 with center overflow is a great reef sized tank for most. I could see if folk were a bit short in the poot, it may make it harder.
I dropped my 300 lower by 2 inch and gained an inch of height on the tank so it's an inch lower. The height of the stand is more important I think for maintenance than depth of the tank.
I did 6x2x2 stand at 36-38. I like the height of the stand for viewing from the couch and like the depth for scape purposes. Just wish I was taller and had longer arms. I do have to use a step ladder any time I need in the tank. One thing I wish I would have done differently ia the mounting for the lights. I wanted some thing where I could swing them out ou the way like TV wall mounts, but they didn't give me the reach over the tank I needed. Planning and triple guessing everything is not a bad thing when your planning a big build.
40" is perfect even w a 24" tall, use a 4' step ladder ,or 2 step stool ,and i'm 5'4 short
and you can get 3 33" pieces out of a 10" board,3 40" from 10' board.
and it's nice to have headroom under stand.
edit: 240 from 1994- 2018 ,unfortunately only pic i have rt now... photo's still packed from move...
Thanks for all the helpful input.. you all rock...I agree that planning is going to be really important. I think no matter which way I cut it. I will be using some sort of step stool for maintenance. Im only 5'4". You should see me try to get frags from the bottoms of FISHYS frag tank. The arms just wont make it. lol. However, I am leaning rtward a more shallow tank for a few reasons. 24" deep would be MAX.I'd prefer a lower stand for viewing, but I've had a sump for a week, so I don't fully understand the pains of under-tank maintenance. but what this conversation could use is @OrchidMiss with her tank maintenance pic.
I did run into a bit of a snag yesterday. I realized the amount of weight we were talking about with a bigger tank. The location I want to put it is on the main floor of my house with a finished basement underneath. The tank location runs parallel to the floor joists (no bueno). Adding a support underneath isnt really an option because of where in the finished basement that would land (the middle of my rec room). So I might need to rethink the location.... unless you guys have some other kind of idea.