Mature filter media?

[Karliah]

Does anyone know of anywhere, online, to buy mature saltwater filter media? I've only come across one site but it was unfortunately freshwater.
All the LFS in my town have closed so the only thing we have is a Petsmart, who only has FW tanks, and they don't carry live sand at this particular one.

 

[IridescentLily]

I think live aquaria used to sell live sand. I'm not sure if they do anymore but you may want to try looking at the the vendors on their sections here http://www.reefcentral.com/forums/forumdisplay.php?f=78