Sulfa 4 TMP, 1 lb. USE: This is a special blend of four different sulfas that have different absorption rate and solubility. These sulfas are combined with trimethoprim, which potentates each others ability to kill bacteria. Thus becoming a wide spectrum antibiotic and a lesser chance of resistant strains being developed. DOSAGE: 1/4 teaspoon per 20 gallons of water. 1/2 pound (treats 3640 gal.)