umm, what are you trying to keep your res clean from? If you want to keep it clean because dirty is gross then just wash it every res change. antibacterial soap and a scrubby pad. then spray with bleach water, rinse and viola clean, sterile res. If you want fertilizer salt buildup removed use the Florakleen or Clearex in plain tap water for an hour or two between res changes. Running a clearing agent while running nutrients is counter productive to say the least as they draw fertilizer salts away from the plant.