Well, good LR should have never been put in FW. So now it's all dead, and with the additional problem of possible dead stuff on it. This may not be as bad as it sounds, because it may have already been dead, since it came out of a crashed tank. Here is what I would do -
Get a large round Rubbermaid trash can, that is big enough to hold the rock. First cure this container. Fill it with water, and add cheep rock salt to get the SG up to 1.025. It need not be exact. DO NOT ADD YOUR ROCK TO THIS. Let the container sit a couple of days, rinse with FW and fill with FW and let it sit over night. If you do not smell any "plastic or chemical smell", the container is ready for use.
Fill the container with SW, and adjust your SG and temp to what you plan to keep your tank at. Now add your rock. Also add a powerhead and a heater to maintain flow and temp. Add a deli shrimp, and a few pieces of good new LR. You are going to cycle the rock outside the main tank. Yes, it can smell from the decay of the shrimp. Test for the usual ammonia and nitrite to go up and then fall back to 0. As a note, also test for copper. It the rock was ever in a tank treated with copper, it will leach out. This is really bad for a reef. In that case discard the rock and get all new rock.
Once you get the rock cured, set up your main tank, add water and adjust water parameters. Now move the Rock from the curing container to the main tank. You may now see another small cycle in the main tank.
Note the the rock has been seeded and cured outside the main tank. There is a reason for this. Any nitrated produced during the curing process are left behing in the curing container, and not introduced into the main tank. Also, if you do have a copper issue, that didn't get into the main tank either.
In my opinion adding chemicals and other similar stuff to speed up the cureing process is a complete waste of time and money.
? Third will adding nitrifying bacteria chemicals speed up my curing process? Thanks
