Color-change tests are commonly used to measure water quality in aquariums and aquaponics systems. A number of tests use a visual color-match approach, i.e. comparing the color in a tube to a set of colors on a card to estimate concentration. A quantitative approach (using a colorimeter/spectrophotometer) can yield more accurate information.
We have tested color-change kits from API, Hach and LaMotte with our colorimeter. These cover 10 of the most essential water quality measurements for determining aquarium and aquaponic health. With commercial tests, no reagent prep is needed and most of these assays are very easy to use.
For each of the 10 assays listed below we have generated example calibration data which is available for download and use. See instructions on this page. Once the calibration data is imported into your Colorimeter software it can be used to start taking measurements from your own tank water.
We do recommend that you follow the instructions for each test below to prepare your own calibration data. Making your own calibration data will yield more accurate results. This requires purchasing a standard solution of known concentration. You will also need some additional supplies including serological pipettes, a pipette pump and capped tubes. This page has a list of recommended equipment and suppliers.
Measure of carbonate and bicarbonate ions in solution. LaMotte test, 0 - 120 ppm
Alkalinity is important in saltwater aquariums for a number of reasons. Proper alkalinity (142-215 ppm or 8-12 dKH) is vital for coral calcification and skeletal formation; it prevents pH swings, alkalinity burn, coral bleaching, and tissue loss; and it improves equipment performance. It is best to test for alkalinity weekly, or as needed depending on your dosing schedule, in order to maintain a healthy aquarium. Simply put, the greater the tank's alkalinity, the greater its ability to prevent rapid swings in pH.