Agar Drain Solution is designed for used in all plumbing systems including septic tanks. It won't damage porcelain, PVC, stainless steel, cast iron, chrome or ceramic pipes and surfaces. Since Drain Solution is biologically-active, it must not be mixed with disinfectants, sanitisers, hot water, bleach, caustic or acidic detergents as these materials will de-activate the good bacteria and enzymes that are present and needed for the product to work. Available in 1L and 5L.