1. turn off tank
2. siphon most of water into buckets or containers (keep tank water clean as possible)
3. place corals into bucket/ container with small powerhead
4. remove the rest of liverock and cover with newspaper dipped in tank water (keep tank water clean as possible)
5. now that majority of rock is removed you can easily catch fish. Place fish/inverts into one or multiple buckets or containers with small powerhead ( I put one piece of liverock in for fish to hide)
6. empty rest of water and remove sand, discard
7. pack and generally clean equipment (skimmer, pumps, lights etc.)
8. pack truck
9. carefully drive to new location
10. have new saltwater mixed at new location (in extreme cases I have mixed saltwater upon arrival but this is
not ideal)
11. unpack truck, make sure fish and coral and tank water are in new location and that new location has ambient temp around 76 or have heater keeping these containers at temp.
12. move tank inside.
13. fill with NEW sand ( I place some liverock on bare glass b4 filling with sand)
14. use empty sand bag to pour water on thus not stirring up new sand and start filling tank with new water. I use an old rio return pump to pump water from containers into tank.
15. place liverock in tank (mostly without coral)
16. fill rest of tank with old tank water
17. place and turn on equipmnet
18. place the rest of liverock and release fish and inverts
This is the general way I move my tanks (just moved one a week ago). I have moved my tanks in a car close to a dozen times and have only ever lost fish once (lost 2 out of about 15). I don't ever remember losing a coral but I do not keep SPS or exceptionally difficult corals.
Good luck
Here is the tank I moved last week: