WP Total Hardness Back Catalog number: 54156 Manufacturer: ABSOLUTE STANDARDS Availability: In the manufacturer's stock Price on request - + Recommended DF-1278-S 1,2,7,8-Tetrachlorodibenzofuran, 1.2ml x 50ug/ml, nonane Price on request 80403 EPA Method 8040 - Surrogate Standard Price on request 70317 2,3,5-Trichlorophenol Price on request