There is no such thing as "fully cured" LR
because as soon as it hits your tank it will be competing with it's biology for resources. My idea of "cured" LR
is stuff that's been sitting in a tank with fish for a few months, not just off a plane from timbuk-two. The last bunch of LR
I got that was called 'cured' I literally had to boil it because it was full pests and causing ammonia spikes. Then again some dealers *are* telling the truth - in my case he wasn't, and I'm not trying to scare you off.
A few pieces added to an established tank shouldn't cause a problem though, and if the current LR
is in good shape and has good circulation, a minor ammonia spike will be naturally absorbed in quick time. That's the whole point of LR
in the first place. It would not be a bad idea to just keep an eye on ammonia levels for the next 3-5 days. Doesn't hurt to be safe.