Originally Posted by C1RUSx02
my fish store always said "live coral sand"
i'm assuming thats crushed coral ...
... my crushed coral is probably 1 mm big
"Sand" refers to a grain size, and if you have 1 mm grains, that's going to be sand. Both the sand and CC should both be the same type of material (calcium carbonate), but the grain size is different. From what I can tell, typical "crushed coral" is on the order of 5-7mm (at least mine is!). The grain size is why people change it... all sorts of stuff gets stuck in between the grains and can seriously influence nitrates. Also, the grains are too big and sharp to allow many invert clean-up crews to clean it up (sand-sifting star, cukes, etc).
I can't wait to switch mine out! :jumping: