Here http://www.gelstuff.com/seagems.html

and here

http://www.gelstuff.com/beachglass.html

I have the True Blue Sea Gems Crystals mixed with the Emerald and the light
effect on and through them is amazing. In my small tan I have the black
glass sand but the sea gems are wonderful. If you email them, they will
make a suggestion for how much you will need for your size tank.