Review on 🔬 Hanna Instruments HI782 11 Nitrate Calibration: Ensuring Precision and Accuracy in Nitrate Measurement by Todd Phillips

This kit was purchased as a test kit to ensure my Hanna HI-713 Low Phosphate Tester is working properly within the +/- 0.08ppm tolerance range. The kit includes two vials with samples and instructions. First, the instructions essentially call for one vial to be placed in the Hanna Checker for step C.1 and then removed for step C.2, where the second vial is placed after adding the reagent pack (just like normal testing procedures). . The problem is that the instructions refer to one vial as a certified ZERO sample and the other as a 1.0ppm sample. They don't tell you which vial to put the reagent pack in. The vials are only marked with A and B. From routine testing I knew that the water sample used in C.1 is the same as in C.2, only the C.2 sample contains the added reagent. Therefore, both vials must be the same water sample in a certified standard set. I used vial A as the first vial for C.1 and added reagent to vial B for step C.2. This gave results of 0.99 ppm, which is in the range of +/-0.08 for a 1.00 ppm sample. The instructions state that the reagent vial should be discarded after first use, meaning you can store the vial without adding the reagent for later use. Problem- That's why it only got four stars instead of five. It is clear from the instructions and terminology used that two test results can be obtained. One test that can give a result of 0.00ppm and another test that can give a result of 1.00ppm. However, this is not the case. The instructions clearly state that the ZERO vial MUST NOT be opened. This means that one vial is your NULL (NULL as in the base sample for C.1) and not the 0.00 ppm test. You will need to open the other vial to add your reagent pack. As mentioned above, vial A was used for C.1 and was NOT opened. Vial B was opened and used for step C.2 with reagent added (this order was used simply because it made logical sense to me). The instructions do not specify which vial to use for which step. Technical, since both bottles must contain the same water sample. You can use either A or B as a template for C.1. Just make sure you don't open a vial that has ever been used for C.1 and that you use the leftover vial for C.2. Summary. In short, the test worked correctly. The sample was certified at 1.00ppm and Hanna Checker showed results of 0.99ppm which is in the range of 1.00ppm +/- 0.08ppm. Before starting the test, open only one of the vials and add the reagent. Once the test has started, use the unopened tube for step C.1 and the tube into which you added the reagent for step C.2.