first step
before using these products, would be to clean the holding tank. An easy method is to fill it 1/2 way with water (through the deck fill cap)...add a box or 2 of baking soda, add more water. Go sailing on a windy day to slosh this around good and then go pump out....After this I would then use KO or ordorless as a treatment product.Also, make sure your holding tank vent hose is not blocked as this will severly effect what can be sucked out at the pump out station. You also need good ventilation (clear vent hose)and oxygen for the KO to work by growing the "good" microbes.