Limpets and Coralline Crew: Well after trying to figure out what I can't grow coralline algae in my tank, I think I have finally identified a suspect.  I have a few of those odd little creatures known as limpets (Elephant Snail, Keyhole, etc.) and according to an article by someone named "Steneck" http://academics.smcvt.edu/dfacey/AquaticBiology/Coastal%20Pages/Limpets.htm These things only eat coralline!!   It really makes sense now because I could see little patches of coralline one day, only to wake up the next morning to find them vanished!  All water parameters, Ca, dKH, etc. are all perfect - no phos, no nitrates, etc.  I guess I'll continue to let them battle it out (I refuse to attempt to remove one of the limpets for fear of damaging him) and see who wins - right now, it's no contest!  You agree that this is possible? <Definitely. These are voracious grazers.  Best, Chris>