i switched not too long ago in my 10 gallon...i put the rock in a container and covered it with water...took my crabs, snails, and fish, and put it in a container...took out as much water i could into another container...then took the cc out...which actually was when the mess started....i still had some water in it, and i was taking it out, it got really dirty...not fun....and i ended up having to add some permade saltwater i had because of the water i had covering the rocks...but after i had taken the most of the cc out, i put in the sand, and then veryyyyy slowly added the sand...then the way, rocks, crabs,fish,etc. it was clowdy for an hour or so, but cleared up, and looks soooooo MUCH better than the cc i had...i love it! here are before and after pics. i dont have my tank loaded right now, but i think it still looks great...all in all, it took me one and a half hours to complete...it was harder than what i expected, but definitely worth it!!
That is my opinion.
Luke P :happyfish