Raritan "PCH" Cleaner Gallon PCHGALConcentrated (1 part C.H. to 5 parts water) C.H. The most effective alternative to removing uric scale from deep inside black water systems. Specifically formulated to target uric scale and calcium build-ups, cleans sewage systems from toilet to tank. Non-toxic, biodegradable and safe to use with all types of materials commonly found in black water systems.