I bought a 3lb. shelf rock yesterday. I am not sure if it is kaliena rock or not but I am leaning in that direction because it is not porous. Last night I counted 25 chitons on it. Is this good or bad. From my understanding they grow very slow and only eat algae. Do people buy these at the lfs or is this just run of the mill hitchhikers like pods? The lfs says the rock has been in his tank for yrs.