Base rock?

[AndyL]

Does anyone have (or know of where to find) some nice base rock? I need some for the new pred tank, but so far, all I've run across is big ugly solid hunks of granite(?), and texas holey rock - that costs as much as live rock. Found some volcanic rocks, but I need some footballish sized peices, and it all seemed to be smaller than a baseball in size.

LMK,

Andy