Substrate? Sand?

[CrGiants]

I have had a 30-gallon aquarium up for about 16 months now. I have live rock, and a crushed coral substrate, mixed with a smaller substrate, equalling about 2-3 inches deep. I want to add sand. Should I take out the other substrate and add sand, or do I just add the sand to the substrate I have now?

Thanks,

CR

 

[esmithiii]

This link is probably exactly what you are looking for:
http://www.reefs.org/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=1&t=029053