[prow]

cool thread mike. something i think most never really think about. good topic for sure.

for the lbs/gal rule thing i dont go by that at all. i use it more like the 2" or 1", whatever it is, fish rule. just too many variables. like the fact some corals up take mass nutrients thus the rock has less to deal with, other corals not so much. just like fish anthias, tangs whatever have very different habbits and effects on the tank and its filtration, not just their waste but what they eat aswell. then there is the sulfer cycle which alone, with a holistic view, makes it almost impossible to evaluate LR's nitrogen cycle. but we do need a starting point, lbs/gal for rock type might be something more useful. geussing here maybe something like 0.5-1lb/gal for low density, 1-1.5lbs for med density and 1.5-2+lbs for dense rock.

for aquacultured rock i do think you need more lbs to get the same surface area. simply because collected rock has had years, no decades, no centuries, well you know, for creatures/bac/ect..to make a home in. aquacultured just has not had as many things clear spots, which increases the surface area, to call home yet. even denses collected, i would think, would have a greater surface area of a given mass.