Formulated concentrated treatment to treat septic tanks, once a year. Treatment: 1 qt bottle works on tanks up to 1500 gal. No. K37-Q-C1500-4: Container Size: 1 qt, Septic Size: 1500 Gal., Usage: Every 2 Months, 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!