Sand?

[Charlie Greiner]

Not really, most of the silica will not be soluble. Just like the glass on a tank is not completely soluble and the diatoms diminish over time. I am not sure but it's probably just the surface layer that loses some silica molucules.

Charlie

 

[mostlycichlids]

You can also use sandblasting sand which is also cheep and you can get it at stores like menards. Sandblasting sand almost needs no rinsing at all.