crushed oyster shells

[active]

would there be any problems with using crushed oyster shells for substrate?
i have used crushed coral in the past and now use aragonite sand.
this is just going to be a thin layer not 2 or 3 inches thick, just to take the dullness from a bare bottom frag tank. i myself wouldn't think there would be a problem but i thought it a question for someone who knows a little more about chemistry.
thanks

 

[cloak]

I don't think you'll have any problems with the oyster shells. I used to use a fine layer of puca shell on top of my old DSB, and that basically looked like crushed shells of some sort.