Watkins Natural Lemon Toilet Bowl Cleanser works against even the toughest hard water stains on your toilet, sinks, tub and tile! Use this cleaner to decalcify your toilet. This cedar-based formula is one of the least acidic or caustic cleaners on the market making it safe for septic systems. And because the formula is made up of replenishable and sustainable ingredients, you leave the smallest possible footprint on the environment! (710 mL/24 fl oz)