I have always believed the idea of controlling holding tank odors is something created by the chemical industry to sell products rather than to alleviate a problem. For those of you who swear by chemical use did you have odor problems that led you to use them? With so many of us not having odor problems without chemicals why not at least try plain old water?
Oh, for those of you who believe you add chemicals to assist in breaking down the waste you are simply wasting money. As some others pointed out RVs have holding tanks not treatment systems. Kind of reminds me of all the snake oil salesmen that sell products to help septic systems break down wastes.