I guess the point that I was trying to make is that although an urchin does eat coralline, there is no way it can, or could keep up with the growth that I have.
There is 165 lbs. of live rock in the tank and I did wait for the tank to be well established prior to adding one and do keep the calcium levels above 400. At this point, the coralline is growing faster than it can eat it.[FONT="] [/FONT]