Hi all. Just a quick clarification? I put some IAL Indian Almond Leaves, in my tank and everyone recommends you take out any activated carbon when adding these because they would remove the tannins. So I know the black pebble looking things that you can put in media bags are activated carbon but, do basic regular old filters have activated carbon in them? If not, why are they black inside and what is actually filtering my tank? I also have a black prefilter sponge..thing. Would that have activated carbon in it? Thank you all.