Yes there are a few silica sands for
fw but the only one I recommend is pool filter sand or pfs (unless you want some black aquarium specialty sand which is ok in
fw too) which is pretty cheap usually found at walmart, lowes, meijer, home depot or pool supply shops. Rarely over $13 for 50lbs. A lot of people use play sand in aquariums but it can cause problems because it's so finely grained.