Lol. I`ve learned the hard way to wash! I use the big block of canadian thats normaly like $8(Mine was $2) I agree vfts are pretty tough to nutrients if they are mature...I use industrial quartz sand wich I tested with phospheric acid and it didn`t buble (If you put it on concrete it would burn a hole though)...pretty powerful stuff..and the sand is good although I use a 2\1 ratio with peat,becausee it`s a little bit fine compared to like perlite