this is how i transfered a 20 to 55..... i bought new sand and filled new tank about half full (ran a ph) with new sw. after everything settled in new tank, i began the process. first, i didnt have anything for the live stock for to stay in, so i emptied the tank til just above the lr and added this water to the new tank (slowly). i then gathered all lr and added to new tank and aquascaped. after this was finished, i then got the live stock out of tank and put in bags and "drip" acclimated for about 3 hours. during this process i gathered what sand out of the old tank that wanted in the new tank. after acclimation, i added live stock and all is fine since..... all in all, took me about 6 hours, but def worth it.... hth