If you have a hard time finding one on your own, call a local mason and ask them were they get there stone from. there's usually a local yard were the masons get all there stone and sand from. These places have all kinds of rocks, just stay away from ones with rust on them or one that seem sandy(made of sand).Local Rockery? Wish i knew of one around here. Never had much luck finding It at landscaping plases either (not that Ive looked all that hard) I may have to do a bit of researching for the future. What I have now will definatley not be enough when i get the 150 gallon. Gonna need a lot of rock for that one.