As bacteria coat the sand particles they become heavy enough to settle. Adding the LR
will get your cycle going so don't worry about. Once it settles and you can see the rock again, use a turkey baster (new and rinsed) to blow the sand off the rock.
I added about 300 pounds or aragonite sand to my 125 when I removed my cc. It took about a week to settle. I could not even see my LR
for 3 or 4 days. Today a sand storm will clear in less than hour
once the source of the storm has stopped (ph pointing at the sand bed