Question: Can i use activated charcoal powder in my filter instead of potassium permanganate? - Charlotte Answer; Hello Charlotte, You can absolutely use activated charcoal in place of potassium permanganate. Activated charcoal has a much longer life span and higher capacity for chemical uptake. You can use either our 4x8 or our 48C-AW. PP will oxidize chemicals upon its surface while activated charcoal...