Walex Products - Walex Bio-Pak Tropical Breeze Holding Tank Deodorizer. Natural Enzyme Deodorizer & Waste Digester. Bio-Pak provides portion control and is easy to use with no messy liquids - just drop it in! The environmentally friendly enzyme formula starts working immediately to control odors and break down waste and paper in the waste tank. Continued use ensures that pipes, valves, and seals will be trouble-free.. 10-pack. Scent-Tropical Breeze. Liquefies all types of toilet paper, eliminating the need for special toilet paper!. Removes odors and breaks down waste and paper. Biocide-free. Formaldehyde-free. Zinc and Copper Free. Safe for septic tanks. California Compliant