hard to say . i had 60lbs of it in a 55gl for about 2 months, then moved to the 90gl, started to cycle some more, added 50lbs more rock, looks like it has started a bit of a cycle too. i have a canister set up with carbon, but i need to get some gfo. was going to try to get in on the BRS group buy, but i might be a little short on money. was thinking of asking if someone could spare some for $5-$10. and thx for the compliment. i had to change it up a bit. had to remove most of it to catch the banana wrasse, it was attacking the tang, and the poor scopas started to show signs of ick.