First you do not want contaminants in the water of your reef system. Secondly if you are setting up a new tank, there is no reason you should end up with a milky white mixture in the first place. Since I had the time, I wanted to demonstrate the right and wrong way to fill a new tank. If you are trying to avoid the white milky stage, the photograph on the left below is of a tank that was first filled with water, and then sand was added by pouring it directly from the top.
This photo was taken a day or so after the initial pour and the water will take nearly a week to clear, and a month or so for bacteria to colonize and make the bed a bit more stable so this type of thing does not happen again when the bed is disturbed. Now that you have seen the incorrect way, the way to avoid this mess is you can simply put the sand in first, but the trick is really how you add the water to the system after that point.
There are two photos below which demonstrate how easy this step can be. The photo on the left is off the tank with the five inch sand bed in place, the water is being trickled in from a small hose connected to a garbage can containing my saltwater. It is important to add the water very slowly to remove the impact of the stream hammering the sand. The photo to the right is of the same tank later that afternoon. The water was topped off and all I had to do was run my hand around the perimeter of the tank to
remove the fine film and the water was perfectly clear and ready for me to gently add rock and fish.
As mentioned previously with respect to my concern for the optimum current I have and still am considering operating some of the tanks with nothing more than live rock, or a combination of rubble live rock completely covering the sand substrate. The combination method of rock covering the substrate certainly goes against practical knowledge. Upon some recent discussion with Dr. Shimeck, he had suggested this method to meet my objectives of cultivating a food chain in the system and keeping the sand intact against high current, which is a challenge in a twenty inch deep tank.
The amount of rock rubble over the sand is my primary objective and my interest is in defining the point where it becomes a hindrance to the DSB. Until I experiment further I may use just rock rubble in my dedicated small polyp stony system which I would like to hammer with current. Eliminating the DSB will certainly be like eliminating a part of the food chain, here in lies my concern. I would rather create an ecosystem, than have the tank dependent upon supplemental feedings.
One idea I am experimenting with is having a remote DSB within the tank and an area protected from high current. However, I am months away from creating that atmosphere, and have many hurdles to cross in the mean time.