The HI740216 Test Tube Cooling Rack is able to hold up to 25 test tubes measuring 16 mm in diameter. When paired with the HI839800 COD Test Tube Heater, customers are provided with an effective solution to their testing needs.

After performing the heated digestion reaction for COD, total nitrogen, and total phosphorus analysis, the test tube heater is turned off and the blank and reagent vials are allowed to cool for approximately 20 minutes. The test tube vials can are carefully removed from the test tube heater and placed in the cooling rack. Reagent vials should be near room temperature prior to determination with a COD photometer.