Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
"...reactor sand, runway traction sand, torpedo sand, pump sand, pool filter sand, play sand, sewage sand, mason sand..."
are all a silica/quartz type of sand.
If you get a graded product, all the particles are the same size, and this will not compact in an aquarium. Pool filter sand and blasting sand are the most commonly available products like this.
Play sand is a product with mixed sizes, and lots of fines. This is the one that will compact in the aquarium. It is generally safe to use 1" to 1-1/2", but by the time you get to 2" deep that is a bit risky.
Sand made from limestone, coral or similar origin is also available, and this is the material that will work in a marine tank or hard water fresh water tank (Rift Lake Cichlids are the most obvious example). These materials add minerals and carbonates to the water, and raise the pH. Aragonite Sand (found in fish stores) is one of the most commonly available products.
Many of the minerals in lava or other rocks are locked up in a way that they are not available to plants, so these materials are not really nutrient sources, even when the material has been ground into sand-sized bits.