I might try just adding some darker colored sand and stirring it in just a bit. Over time the finer sand will get sucked out and be gone. Meanwhile you have not disturbed the whole tank needlessly. When i've used all purpose or playsand in tanks, I've found that over time the smaller grains do get sucked up and I do need to replenish the sand. The look of the sand gets somewhat more "grain" to it. I just add sand to a small bowl and gently take it to the bottom and slowly pour it out so that I don't have to deal with the cloud of silt.