In general it is not a branded product, you are buying a mineral that is crushed and sieved to a particular grain size. Look for 100% silica and 20 grain. You don't say where you are in the US but I have had best luck buying from a pool and spa chain called Leslies.
Brand matters if you want something other than the white silica. Red Flint has a very nice PFS and aquarium sand in #20 size. It would appear the two products are the same. Whether they are available to you is another thing.