you don't need to buy another bio-spira or any more bacteria, it won't do more. you almost done cycling, but i think it takes so long because you don't have anything in the filter for bacteria to settle on. don't change your filter until everything is steady for some time. if you don't have a biowheel you need to add a sponge to your filter that would make a good home for bio bacteria, but don't take out the filter pad that you have been using for a while. also don't shuffle your gravel and don't overfeed. also if there is toxidity issue, "Prime" it. with bio-spira it's 14 days to cycle, only adds once, that's what the company that makes them told me