The brand I bought was called Mystic White II pool filter sand. It sells on Amazon for $9.49 for 50lbs. But because of the weight, the shipping was $30 per bag. I bought 100lbs for $77. If you can find it locally, I definitely recommend doing so. Like I said, I wish I had found this thread sooner. But if you want instant gratification and willing to pay for convenience, here's the link:
http://www.amazon.com/Filter-Sand-5...sr=8-1&keywords=mystic+white+pool+filter+sand
As far as washing it, I rinsed it and it actually didn't cloud the water up that much. But I washed it anyway since I was mixing some crushed aragonite into it for buffering capability. And when I added to the tank, no cloudiness whatsoever! Hope this helps!