I know you love metal halides and acros a lot just like me but since you have a 2x2x2 tank, have you thought of a NPS tank only. Its a lot of work and different beast all together to successfully keep NPS gorgorians, dendronephthya, balanophyllia, dendrophyllia and other NPS with species like crinoids.
Its a whole different ball game together and will make you do everything different than an acro dominated tank. But at the end, the beauty is undeniable and most importantly will keep you crazy busy with new ideas and new reefing ways.
I have the same dream to set one up with automated food dosing using a freezer but currently just happy to be back in the hobby with my dear acros and would take on NPS once I have managed to grow the acro frags to decent sized colonies.
Just to inspire you here's links to 2 of my most favorite NPS tanks of all times :-
http://www.advancedaquarist.com/2011/1/aquarium
https://reefbuilders.com/2012/11/12/sun-coral-tubastrea-aquarium/
Regards,
Abhishek
I think the answer is right in front of your face and you're not even seeing it. You said that you've got fish older than ppl got cats and dogs, so letting them go isn't going to work, right? Well I've got one question for you. "Will they fit/live in that nano tank of yours?" If so, then there's your answer. From here on out, you've got a few decisions to make:
1. Do you have enough time to take care of fish? If so, then sell off your corals, and just keep a FOWLR tank.
2. If you've got time to take care of corals also (e.g. water test, dose, etc, etc) then move some of your most prized coral and live rock pieces into the nano. But instead focus on it being the most bad@$$, most insanely sic looking slice of coral heaven anyone has ever seen!!! If you don't have the time resources to make your current tank look decent, why not not just down-size and make your new nano look "Tank of the Month" worthy???
By setting up a nano, water changes and cleaning will be reduced significantly. You could even be smart about it and store a large vat of saltwater ahead of time. You could also break up the maintenance of it. Scraping the glass down could be done on one day, and water change the next day. It'll be a lot easier doing a 5 gallon water change twice a week, because it's only one bucket per water change. You might not even need to dose nopox if you do two slightly larger water changes.
Now back to the nano tank itself. Are you happy with it? Or do you have to squint for it to look pretty to you? Because if its not a home run right out the gate, then why not treat yourself to a shiny new tank. Perhaps a nice all-in-one, or you can even splurge and get one with a stand and sump. Whatever you get, just make sure that you're honest with yourself and are happy with it.
As for your large tank, you don't even need to break it down, at least not just yet. You can leave it running and slowly take out the choicest pieces of live rock and corals for your new nano, and then slowly sell off/ trade / give away the remaining live rock and corals. By moving your current live rock and rubble/ sand/ etc into the nano, you'd avoid a cycle altogether. INSTANT GRATIFICATION!!!! Once you've emptied out the tank's contents, you can wait for a long weekend to decide to breakdown the tank. Hold onto to the tank for about a year and figure out what you want to do, whether it be to set it up again somewhere down the road, or sell it altogether because you enjoy the smaller nano which is easier to maintain.
My point is, you can go slow and easy and break it up into small, bite-size pieces. You don't need to go all-in all at once. Just keep it simple and be honest with yourself as to how much time you truly can devote to the hobby and what will make you truly happy. After all, this is a hobby in it's essence, and if it don't make you happy, then why keep banging your head against a brick wall?
Good luck!!