Don't try sand from the river to many yuckies to contend with. I use play sand it's cheap and works

I just bought 2 50lb bags of silica sand from Menards for $4.16 per bag. It's already washed (states that on the bag) which is nice. I took some out and rinsed it in a bucket to make sure it's really clean and it was. Added water to the tank (75 gallon) and there was virtually no cloudiness at all. I put in one of the bags and half of the other and that gave me about an inch and a quarter all the way around.