There will be some die off but in 99.9% of the shipments the rock has very little die off and people can add right to an established tank.
Even though this may be the case, I think it is only prudent that you cure your LR
outside of an established tank, you never know what your shipment has gone through after it leaves the hands of the LR
.com people. I'd hate to be on of the .01% that experiences alot of die off and then plenty of casualties because I put the rock in my established tank.