Has anyone done a DIY filter? Im think of making a real big one to go along with the new DIY tank I want a sump tank at the bottom of the fish tank and have a tower in it with all the filter type of things in this tower the water would trickle through it and end up in the sump then get pumped back to the main tank with one of those pond pump things. Is bio balls any good for tropical fish or are the strictly salt water ? As i dont know how to get pics on here yet its hard to explain but some on who has biult them before would have a general idea of what i am talking about!!!