I just got two big ones and two small ones from Byran this morning (one of the small ones was DOA). While I don't have hair algae issues, I am hoping they will take care of some macro algae that is growing in my frag tanks. I did pick up one back in January, just before the group buys that did a good job of cleaning up my tanks, but like a lot of the others (in Moe's thread link) it only lasted for about three or four months.