Natural Chemistry 04012 Spa Defoamer with Flip Top, 16.9 Ounce Natural Chemistry spa defoamer is specifically formulated for spa water to instantly control and prevent foaming With circulation system running, add approximately 1/2-ounce (15mL) directly to spa water repeat as necessary Compatible with all sanitizers and spa surfaces Non-toxic and will not harm the environment Comes in 16.9 ounce container