Where did you get the new LR
from? Was it cured when you got it? Did you add it before the tank started cycling again? If not, that's what probably started the new cycle.
If this is going to remain a FOWLR
tank you can keep the bio-balls. The nitrates will remain on the high side but that's ok.
If you think you want to go reef some day (and you probably will), now would be a good time to remove the bio-balls as the tank is cycling, and the fish are in QT