if it's good live rock, with no die off, you should be just fine. You'll have a sand storm for awhile and will probably get a diatom bloom. After that, you'll just be fine!!
If you can use a funnel with a piece of PVC pipe, you can keep the pipe just off the bottom and pour the sand through the funnel. This will help keep the sand storm to a minimum. Also, if the sand is wet, it'll be less likely to get blown around. I'd also recommend turning off your flow while adding it. Another thing to keep in mind is that you may have to adjust your flow once you have sand in your tank.