Original formula takes only 4 oz to treat an entire 40 gallon tank in any season. Also available in an easy-to-use bottle with a convenient built-in reservoir for measuring. Eliminates odors and lubricates sensors. Safe for all septic tanks. No. 40227: Size: Gallon, Pkg Qty: 1, Package Type: Bottle Thanks for shopping Hipp Hardware Plus's Online Store for all your DIY and Home Improvement needs. Remember Hipps Help!