You may want to in a seperate small container fill 3 or 4 media bags with porous substrate and inoculate with a maufactured bacteria culture such as fritzyme, biospira, or dr Tim's branded bio cultures . I let them soak in the solution overnight at least so that the cultures permeate the substrate . I toss a bag in with every tank change or new treatment change . This so that you don't have a nitrogen spike . You are not alone for that has happened to me