We only moved about 20 minutes and we have both properties simultaneously, so here's what I did. Actually, I did it twice. I moved my 60 gallon to a 75 gallon and my 10 gallon to a 15 gallon, though I did them on separate days.
Ordered a new tank. Set up new tank at new place with new sand and water (about a week before doing the tank transfer). Luckily the tank was in stock at IM. I had heat and return pumps, but no other equipment on the new tanks as it was on the old ones.
Bagged the fish and put in a cooler to insulate them. I think this would be fine for a 3 hr drive, but could use a bucket if needed.
Bagged any of my smaller coral and all of my inverts (separately, of course). My LFS let me take as many bags as I needed when I asked to buy some.
Used buckets and Brute bins to transfer larger corals and roughly 60 to 70 lbs. of rock. Most of the rock was either fully submerged or mostly submerged. One piece (my green encrusting monti) was so massive there was no way I could transport it under water at all. So he got moved dry.
Drove all livestock to new house. Got the rock into the tank, removing the water that the rock displaced. I had the fish bags floating while I did this.
Acclimated the fish and turned them loose in the tank. Added bottled bacteria, even though I had all my live rock in there.
Went back to the old house and gathered the rest of my equipment including skimmer, power heads, lights, dosers, etc.
Installed the lights right away and added the other equipment to the tank over the next few days.
I only had a mini cycle on the new tank - about 2 days where I had detectable, but low ammonia and nitrites, and then it was fine.
Its not a good time, and 3 hours apart does make it harder because you can just pop over easily. Given my close proximity, I did not feel the need for heaters or bubblers. With 3 hours, I still probably wouldn't use them, but I guess it would depend on how sensitive your critters are. All of my fish and inverts survived, including some I didn't even know were still alive in my tank LOL. I thought the coral banded shrimp I added and never saw again was dead, but no, just a great hider. Interestingly, I see him more in my new tank now. The one big issue was the green monti I couldn't transport in water. Most of it died. But not all of it. The edges are still alive, and it's such a prolific grower that I expect it'll fully cover the dead parts within a year. The thing was probably 14X20 before the move and now only a small part is alive (large parts of it I broke off intentionally because it had connected 3 big rocks that I wouldn't have even been able to get out of my acrylic tank without breaking apart). I also had a fair amount of coralline die off, especially on the tips of the rocks that may have had air exposure. But all the fish, inverts, and other corals did great. You can check my build thread for some photos.
