I am going to cut and paste what I recently replied in another post....here it is:
.....Simply put,
curing is getting the old dead biology out of the rock, and
cycling is putting new live biology back into the rock. It seems today too many are skipping the cure part and not believing it's necessary. I've actually been beaten up with comments in posts that it's not necessary. I hear comments like, "It doesn't need to be done," "It's XYZ brand of rock and does't need it,""It's pre-cured," etc. As far as I'm concerned, these are the folks that post two months later and want to know what to do about a terrible algae or cyano problem....and why are my nitrates and phosphates through the roof. I also think in some cases it's our impetuous youth...and I can say that because I'm a grumpy old man.
Now dry rock has varying amounts of old death within, and because of that some rock cures faster than others. What needs to be done for curing is letting the rock sit in water with a little flow (if done indoors, no heater needed...and no light), and simply allow the old death to decay and leach out. Bleaching helps in this process in that it jump starts the hydrolysis of the dead stuff. (BRS did a "TV" spot on this
HERE) What you do, while your rock is curing, is to monitor nitrates (and phosphates). You can test for both, but I usually just do nitrates with an occasional phosphate. You should see it climb pretty fast. When it gets high (and I'll say about a week), do a water change....100% water changes is just fine. Again, let it soak....monitor...do a water change (for the sake of argument, week two). Usually this first and sometimes the second week are pretty stinky.....you've been warned. Continue to monitor and do water changes as needed. You will eventually see N and P level off and start to decline....the end is getting near.
Now curing and cycling can occur concurrently. I would not recommend starting the cycle until after a number of water changes...especially the first two or three. A fast cure is about a month, but more typically (especially if "dirty" rock), more like two months.
Now I'm in the process of starting a cure right now. I'm going to try something new (for me anyway). The first two (and maybe three) water changes are going to be RO/DI water only. After which I'll change over to saltwater.