I still have the algae problem in my 30 gal tank so I will have to buy more clean up crew but it is looking much more better when I only had 4 hermit crabs and 4 snails now I have 8 crabs, 2 horseshoe crabs to sift the sand, 6 snails but I will have to buy more snails cuz the other 3 died overnight when those 3 fell from the glass when I was sleeping (I think)