Is it crushed coral or just plain gravel?
Either way what Jerry said is right, ditch the gravel and get yourself a sand bed going.
Here is how I would go about it.
1. Get yourself a tank or container big enough for your fish, LR, coral and clean up crew.
2. Siphon out some water into the container from your tank (do not stir up the gravel on the bottom.
3. Get a heater and powerhead going in the container (make sure the temp is the same as your tank).
4. Pull out the LR and coral from your tank and put it in the container. Make sure you have enough water in the container to cover the rock and coral.
5. Remove all the fish and cleanup crew and place them in the container.
6. NOW siphon out the gravel from the bottom of the tank.
7. Add your sand (I prefer Seaflor Special Grade Reef Sand but you may want to get finer sand than that).
8. Let the tank settle out (it will look terrible for a while) run your skimmer to remove some of the particular matter.

Once the tank has cleared up pretty much go ahead and add the items you have in the container.
I like to do it this way to keep the LR from getting all coated with the powder like residue that the sand will leave when added to the tank.
I hope this helps you out a bit, I know it is alot of work but it would be best in the long run.
Like I said this is just how I would do it, you may get other suggestions on this or some other forum.
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