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.
We are also working on adding new assays as time permits. Notes on development of other assays is on our Wiki page.
Alkalinity (KH, carbonate hardness) - LaMotte test, 0 - 120 ppm
Ammonia - API test, 0 - 8 ppm
Calcium Hardness - LaMotte test, 0 - 200 ppm
Iron - Hach test, 0 - 10 ppm
Nitrate - API test, 0 - 200 ppm
Nitrite - API test, 0 - 2 ppm
Phosphate - API test, 0 - 10 ppm
Potassium - LaMotte, 0 - 50 ppm
Sulfate - Hach, 0 - 300 ppm
pH 6.0 - 8.0 - LaMotte test