Never add or remove more than one inch at a time. If you add more than one inch then you are burying the living organisms in the sand and they die. You know what happens when living organisms die in the tank. They release trates and phates into the system. If you remove more than one inch at a time you are removing the beneficial living organisms, and more can actually release anaerobic organisms into the tank. Some of these organisms are very toxic to your aerobic marine life.
If you maintain a sand bed of one inch or less, it can be, and I stress can be OK to stir as A browning suggests, but a deeper bed means it is a no no to disturb for reasons mentioned above. And although sandbed depth is an opinionated subject, I believe it is more than a personal taste and that although there may be no optimal depth, there is a range to avoid. Anything between 2+ inches and 4 - inches is considered no man’s land. This is just deep enough to be problematic and not deep enough to be beneficial. Other substrates as well can be just as pretty and easier upkeep than a sandbed. Sandbeds are beneficial when trying to keep particular critters in the tank. Other than that shallow beds are for aesthetic purposes only.
Merry Skerry