The alkalinity level in a marine aquarium is significant to test for and having accurate testing equipment that is easy to use is just as critical. The Hanna dKH Checker is just that, with a large LCD display and a photocell based testing procedure, all the guess work is removed allowing you to get accurate and repeatable readings. Performing a test with the Hanna HI772 dKH Alkalinity Checker typically takes less than 1 minute, and we do have a few tips to make it even easier. Step 1. We like to use a 10mL syringe to retrieve a sample of the tanks water, and then fill one of the testing cuvettes up to the 10mL line on the outside of the vial. Step 2. Power on the checker by pressing the black button on the front of the unit Step 3. Clean any fingerprints or water marks from the outside of the cuvette and add the tank water sample to the checker when the LCD screen reads C1 and press the black button again. Step 4. When the controller is flashing C2, you can remove the cuvette and add 1mL of reagent to the vial. Gently invert the vial 5 times and place it back into the meter and press the black button one more time. The LCD screen will then display the reading in just a few seconds. Tips – It is essential to keep the testing vials clean for accurate and reliable readings. We suggest cleaning the cuvettes with a soft dry cloth before placing them into the checker. We also highly recommend cleaning the vials with RO water before and after each use.