what's cruched??

Or maybe it's supposed to be "crunched" - to crush, grind or chew noisily.

Or "crushed" - to press or squeeze out of shape; mash. To oppress.

???

yes it would be fine as far as the bacteria and other critters you want that come along with live rock and live substrate. its obviously much more pouros being that its crushed but i prefer using both because for some reason you always get neat surprises with live rock. As far as cycleing the tank is concerned and adding that beneficial bacteria that you need to breakdown waste live sand is basically just crushed live rock or crushed coral. The other reason i like live rock is that you can do nice rock scaping with it and give a very natural oceanic look to the tank. if you plan on keeping certain sharks or rays that dont like to much rockwork and prefer the open swimming space than just going with the live sand and maybe just some liverock is just fine.

You might have misspelled the word. There is a crouched which means to bent or kneel.