If you are using flawless finish from advanced nutrients you dont need anything else trust me . You could try it as an experiment but in all reality you really really dont need too , the agents in Flawless act like little vaccums while providing your plant with the essentials that it needs while it finishes up . The hydrochloric acids in the flawless finish are strong so to use them in combination with another flushing product might be over kill so like I said I would do it as an experiment but not a regular thing unless it worked really really really good :) . I hope this information helps you on your journey to the finish line ! -Happy Growing!