Hanna Instruments - Checker Handheld Colorimeter Marine Calcium

Hanna Instruments - Checker Handheld Colorimeter Marine Calcium

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The Hanna Marine Calcium Checker® bridges the gap between simple chemical test kits and professional instrumentation. Chemical test kits have limited accuracy and resolution since they rely upon the human eye to discern differences in color. Professional instrumentation incorporates a light source such as an LED or tungsten lamp with a filter and a light sensing detector to precisely determine absorbance and ion concentration. Professional instrumentation offers greater resolution and accuracy but can cost hundreds of dollars. The Hanna Marine Calcium Checker® uses a fixed wavelength LED and silicon photo detector to provide the accuracy of professional instrumentation at the affordable price of a chemical test kit.

The HI758 Checker® HC (Handheld Colorimeter) provides a simple, accurate and cost-effective way to measure calcium. Required for the development of calcium carbonate skeletons of coral reefs, calcium is a crucial component of marine waters. Designed as a more accurate alternative to chemical test kits, the HI758 provides quick, accurate results in a few easy steps.

The Benefit of Testing for Calcium


Calcium is an essential ingredient to a healthy and functional reef aquarium. Corals and coraline algae require calcium for calcification and growth, so much so that an aquarium stocked with these organisms require regular calcium supplements in order to maintain healthy levels.

A variety of commercially available supplements exist, from calcium salts to buffered calcium supplements, which raise both calcium and alkalinity. Many aquarists set up a regular supplementation schedule to maintain proper calcium levels. However, regular calcium monitoring is crucial to a healthy reef aquarium, even if such a system is in place. This is because as corals and coraline algae grow and mature, their requirements for calcium tend to increase. As a result, the growth of the aquarium might outpace the calcium supplementation regimen.

The ideal range for calcium in a healthy reef aquarium is between 380-450ppm. Values below 380ppm may slow the growth of corals, whereas high levels of calcium (>500ppm) puts the tank at risk for calcium carbonate precipitation (limestone formation).

The Limits of Traditional Color-Change Test Kits

Many test kits on the market rely on a color change that needs to be judged by eye. These are notoriously difficult to use, especially in the lower ranges. The Hanna Marine Calcium Checker® HI758 bridges the gap between simple chemical test kits and professional instrumentation. The one-button design makes testing for calcium a cinch to use.



  • The Checker HC easily fits into the palm of your hand or pocket
  • Ideal for Aquaculture and Aquarium testing
  • Easier to use and more accurate than chemical test kits
  • Large, easy to read digits
  • Auto shut off
  • Single battery operation
  • Use for quick and accurate on the spot analysis
  • Single button operation: zero and measure



  • Range: 200 to 600 ppm
  • Resolution: 1 ppm
  • Accuracy: +/- 6% of Reading
  • Weight: 64 g (2.25 oz.), 
  • Battery Type: 1 - 1.5V AAA

How it works:

  • Press the button to power the meter on. Notice “Add C1” appears on the screen - you are now ready to begin testing.
  • Using the 1mL syringe, add 1mL of reagent A to the cuvette. Then, using the dropper, fill the cuvette to the 10mL mark with deionized water. Distilled water is also acceptable. Once the reagent and water are added, invert the cuvette five times to mix.
  • Using a microfiber cloth, wipe the cuvette to remove any oils or fingerprints from the glass. Then, place the cuvette into the checker and close the lid, making sure it is completely closed. It is important to make sure that the lid is completely closed for an accurate reading.
  • Press the button. Once the screen shows "Add C2", remove the cuvette from the meter.
  • Add 0.1mL of sample. For best accuracy, use the supplied 0.1mL pipette. Note: To use the Hanna Instruments Micropipette, first attach the pipette tip. Push the button to the first "stop", and then immerse the tip into the sample. Slowly release the button to its original position. Then, wait two seconds to catch any drops before dispensing the sample into the cuvette to the second "stop".
  • Once the sample is added, add one packet of reagent B to the sample. After that, cap the cuvette and shake vigorously for 15 seconds. Wait 15 seconds for bubbles to dissipate.
  • Wipe the cuvette of any oils and fingerprints, and place back into the meter. Press the button; The meter will directly display the concentration of calcium in ppm.

Includes :

  • Calcium Checker
  • 2 - Sample Cuvettes and Caps
  • Reagent Start Kit for 25 Tests
  • Battery
  • Instruction Manual