The only time I would rinse substrate before filling is if it was inert to start with. The moment you rinse live sand it, it kills or washes away the live beneficial bacteria in it. The tank will be cloudy for a day or two when fist filling/adding the sand. You can clear it up faster by using the Bio-Magnet clarifier that is included in the bag, and using a 100-200 micron filter sock. Later after the tank has fully cycled and stocked up, say 2 months or so old, you can start gently vacuuming the sand bed when doing water changes. This will pull up and remove the finer silt that has worked to the bottom of the bed. Over the next several cleanings the fine silt will be all but removed from the system and does not harm the bacteria colonies that have developed and very little silt will be kicked up when messing with the sand bed if you move something around.