K.O. is a complete holding tank treatment
It replaces other products entirely. Because K.O. is live bacteria, and chemicals kill bacteria, you'd just be wasting your money on K.O. if you use any other "toilet" chemicals with it except C.P. which is a bio-enzymatic, non-chemical bowl cleaner, totally compatible with K.O. Whether you use K.O. or not, you should never use household toilet bowl cleaners, bleach, or any products containing alchol, pine oil, or petroleum in a marine sanitation system....they're harmful to the seals and valves in toilets...can destroy the electrodes in a Lectra/San (in fact, NO chemicals should ever go into a Lectra/San)...and break down hose.