I bought a bag of sand today at a garden centre in the aquarium section. *It's sold as silica sand, but seems really brown for it to be. *Here's a pic of some washed sand:
As you can see, there are quite a few clear granules, but there are browner ones and even black grains (probably not silica at all). I was wondering if this is safe to use to grow Pings and Drosera. Thanks!