I need to know if I can clean my filters out. They have a lot of gunk and white "fungus" type stuff. I heard that you aren't supposed to clean them because it will mess up the biological arrangement of the tank. I have an Aqua Tech 30-60 Gallon filter. It has two replaceable filters and the two "biofiber" filters(the dirty ones). What should I do and how should I do it? Thanks for your help in advance.