jsut wondering what to do. i have coraline growing on my glass dont know to take it off or keep it on. so what to do?\n \nalso theres some litle white things, there swirled like snale shells, but there very tiny, and hard and is on the glass. dont know if i should take it off or not. i try to scrub it but its very hard. also what is it? thanks!!!\n \nand thers also some reddish/brownish algea on the sand. just a bit. the crabs just killed a snail and i now have 3 left, and i need more. but there not keeping the tank clean like the use to. so how do i get rid of the reddish/brown algea on the sand. thanks!!!