If you use enough of the LS
thats cured and well mature than no but the key word is enough. For a 90 tal tank I would say at a minimum 90 lbs of very mature live sand (not the junk they sell in bags in the store) and 150lbs of mature cured live rock that has not been shipped recently.
Given that much live sand and live rock can be VERY expensive its suggested to get smaller amounts of live sand and to seed some dead sand or dry sand with this live sand and to seed base rock with nice live rock as well as use the shrimp method.
Your still a few weeks away from being able to put fish in the tank and not have to worry about the slightest over feeding causing deadly ammounts of ammonia.