I filled a 5 gallon bucket about halfway with sand and continuously filled it with water, while stirring the sand, and then poured the water out, making sure the sand didn't get poured out with the water. You'll notice the water will be very opaque at first but will slowly become more translucent as you pour out the fine particles that are suspended in the water. I think I filled the bucket and poured it out about 5 times for each bucket of sand and it took about 6 buckets to get my 75 gallon tank to the level that I wanted it.