Just upgraded from a 35 to a 125. Here is how I did it in one day.
1. Started making RO
water a week ahead of time and put it in a 150 stock tank where I mixed salt. Had a few power heads and a heater in it as well.
2. Put live rock I got from a friend as well as dry rock in the stock tank a couple days ahead of time and tested water to make sure there was no cycle going on.
3. Had a spare light on the stock tank to keep corals temporarily (for one day it isn't a big issue but I had a spare light).
4. Had an empty tote with another heater and power head waiting.
5. Starting at about 4:00 PM I moved almost all of the rock from the 35 into the stock tank along with corals.
6. Moved water from the 35 into the tote so fish could be moved immediately without having to acclimate. I also put some of the rock from the 35 in with them to avoid ammonia build-up.
7. Once everything had been moved, out with the old tank and in with the new.
8. Moved all rock from the stock tank over to the new tank and aquascaped in about 30.
9. Added new dry sand to avoid a cycle.
10. Added salt water from the stock tank by pumping it into a bowl sitting on top of the sand. No cloudiness at all.
11. As water levels in the tank started to rise and levels in the stock tank started to drop I moved corals over one at a time leaving my three anemones for last.
12. Once the tank was full and water temp was fine I started up the sump and skimmer and started to acclimate fish over to the new tank.
At 1:00 AM I popped a cold one and admired my work.