Natural Chemistry 04013 Spa Clear, 16-Ounce Natural Chemistry spa clear is a chitosan based clarifier made from recycled crab shells Highly concentrated natural formula; impossible to overdose Very effective with high sanitizer levels Can use in dosage as 1-ounce per 200 gallons for standard rate and 2-ounce per 100 gallons for cloudy water rate Comes in 16-ounce container