Cured or Uncured...what to do?

I'm late to this thread but here's my understanding of cured vs. uncured.

First a few facts as I believe them. The ideal live rock is visibly clean, and almost devoid of algae (you'll always have some algae). This rock works its magic in your tank by being a biological filter--the bacteria within this rock consumes the very things in our tank we don't want there. This biological filter needs oxygen, ample water flow, and a food source. If there's algae on the rock, that algae will compete for real estate, hence, for every visible speck of algae, there's a colony of bacteria that can't live in that spot. For every bacteria evicted by algal growth, the quality of the rock is diminished.

To answer your question, when LR is harvested from the ocean (or from a fellow reefer's tank), it can contain a lot of algal growth on it, and some tiny life inside such as crabs, pods, worms, etc. When rock is trasported, things die, both on the surface and inside the pores of the rock. If this rock is put into your tank at this point, you can expect the bioload of the dying matter to affect your tank by contributing ammonia. Some call these ammonia spikes mini-cycles. If this rock is instead taken to an LFS, or put in a basin in your house, deprived of light, but given ample flow and oxygen, the dieoff will occur in that vessel. The water is changed periodically, (discarding the nasties), and the rock is said to be cured. It is then almost ideal for our tanks: it houses a massive amount of bacteria, and is clean and free of any nuisance algaes.

While this "clean rock" is almost ideal; it can still contain pests such as aptasia, or crabs we don't want, or pests that eat corals, etc.

This is the reason Otty gives above for buying dry rock instead. I think he's right. IMO, dry rock is the best of all worlds. It's very clean when "new" and it brings no risk to the tank in the way of pests. This dry rock will become live rock pretty quickly in our tanks.

So to sum it all up, "cured" rock is not going to deliver ammonia to a tank. Uncured rock will.

There's lots more to consider, like the presence of phosphates in rock, and the anaerobic bacteria that lives deep within the rock's pores that acts only on nitrates, but for your question about cured vs. uncured--I hope that helped.