The important stuff like bacteria will still be alive in the rock. Even if the rock were totally dead(which it won't be) it would be reseeded by the rock already in your tank now. The only thing that will totally die off in that hour is any corals, hitchhikers, algae, sponge, etc... that were on/in the rock. To keep LR alive it needs heat and saltwater, the flow I don't think is necessary but it helps.