Hach does not sell a zero dissolved oxygen standard, but we do sell the individual components to make up the solution.
1. Measure about 150 mL of sample or deionized water into a 250-mL beaker. Add a magnetic stir bar.
2. Add 0.25 g sodium sulfite or the contents of one Silica 3 Reagent Powder Pillow to the water. Stir to dissolve the reagent.
3. Catalyze the reduction of dissolved oxygen by adding 0.1 mL of a 1000 mg/L Cobalt Standard solution to the water.
4. Place the probe in the stirring sample for at least 10 minutes. This solution is good for 30 minutes or more.
Silica 3 Reagent Powder Pillows, pk/100 (Catalog Number/Order Code 27169)
Sodium Sulfite, Anhydrous 454 g (Catalog Number/Order Code 19501H)
Cobalt Standard Solution, 1000 mg/L as Co (NIST), 100 mL (Catalog Number/Order Code 2150342)