Ultra PowrPaks for portable restrooms and holding tanks from CPACEX are formulated to provide continuous odor control and fragrance for up to seven days in the most extreme conditions. Effervescence ensures the packets will dissolve quickly and disperse evenly throughout the holding tank. They are available in five sizes to fit specific applications and climates. They are biodegradable and all formulations contain rich, non-staining blue dye. 800/874-7383; www.cpacex.com.