Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Pool filter sand is a lot cleaner than many other substrates, but is not dust free.
I would do this:
Rinse it in the tank.
Do a water change where you deliberately stir the sand as much as you can to keep on removing more and more of the dust. You might fill and empty several times, or run a constant in/constant out set up.
Finally, drain the water below the level of the sand.
Create hills and valleys, add driftwood, rocks, ceramic mer-people, then plant (misting the plants).
Put a plate or plastic bag over the substrate and fill, running the water in slowly over the plate. 1 gallon per minute max. The water will seep into the substrate with very little clouding.
For a larger tank, once the water gets fairly deep you can fill faster, but angle the hose across the top of the water, do not allow the water flow to gouge into the sand.
There will be a slight haze to the water, but nowhere near as much as to call it cloudy. In my set ups this is mostly gone in a few hours, and really clear overnight.
Add fine filter floss, polyester batting or similar to the filter. You might have to clean it in a day or 2 (once it has trapped most of the finer material that is suspended in the water), but this material is reusable several times.