My suggestions would be use live sand instead because if you use chiclid sand you would have to seed it with live rock and live rock can be expensive. Second buy an ro
unit it will save you in the long run. Third when it comes too a reef the more live rocks the better. For a 55 you should probably go to about 1-2 pounds of live rock per gallon the more live rock the better. Fourth invest in a sump and get a protein skimmer fitted for twice the size of your tank then you can get the cycle going while you grab the equipment and rocks.