If you are thinking of use as a tank additive, then nothing at all will work fairly well if you make sure that the tank is more than half full before you dump. If you do want something, then if Rid-Ex is available it will work very well. We have used it for several years. It just enhanses the effect of the natural bacteria, and in so doing helps to keep odor down. If what you mean is something to clean the tanks when you travel between locations, mix about 1/2 box of TSP with five gallons of water and then add it to each tank. Add another five gallons of water to each tank and then drive to your next site. Once you are there and hooked up, dump the tanks and use them as before. It will work very well.