no matter what anyone tells you, if you do that step-relocate unrinsed sand, it's dangerous and can kill your whole setup.
what you do with the sand:
you rinse it hundreds of times in sections, for hours, until its 100% clean and not one spec of clouding. then you do a final rinse in saltwater of that rinsed sand
then you transport 100% rinsed sand and install it cloudlessly into the new system, and you can't harm anything. if you skip this thinking its safer to move unrinsed sand, it's not, and you can kill all your fish. simply rinse for the win.
people ask me if that harms bacteria and it leaves me scratching my head, because that was covered when I said its the only safe method known, to pre rinse. if you skip rinsing, in order to preserve what is viewed as important bacteria, all your fish can die, so that detail was for sure covered :)
rinse if you want to skip cycle the move. skip rinsing if you want a 10% chance of wipeout.
here's the official sand rinse thread with 200+ tank moves in it, all following the rules with perfect endings:
https://www.reef2reef.com/threads/official-sand-rinse-and-tank-transfer-thread.230281/