i seem to be getting a lot of brown algea on my sand, and i notice there some beneth the sand(i can see against the glass). i try to vacumm it up but i vacumm up all my sand. theres some fish poop under the sand and when i try to vacumm that up i end up vacumming up a lot of sand as well. the inverts i have are sand shifting star, 7 blue legged hermits, and 6 snails. i have a 20G long. so heres my questions\n \nhow od i get rid of the algea?\n \nhow do i not vacumm up sand?? if i cant, do i replace sand with new live sand? \n \n \n \nthanks!!!