Alkalinity Water Testing Kits

  • Handheld Colorimeters
  • Easier to use and more accurate than chemical test kits
  • Dedicated to a single parameter
  • Small size, big convenience
  • Ideal for Saltwater aquariums (HI755)
  • Fresh water aquariums (HI775)

Alkalinity is one of the most important parameters to measure in aquariums. It helps to maintain a stable pH, an important factor for most aquatic life. In seawater, bicarbonate is the largest contributor to alkalinity and is a critical element needed for healthy corals. Corals need bicarbonate and carbonate available to form their skeletons. Without an adequate level, healthy coral growth is not possible. Since bicarbonate levels can be difficult to determine, total alkalinity is measured instead. The alkalinity of natural seawater is typically 125 ppm CaCO3 (equivalent to 7 degrees of carbonate hardness, or dKH). In saltwater aquariums, typical alkalinity values can range from 125 to 200 ppm CaCO3 (7 to 11.2 dKH).

The HI755 and HI775 Checker®HC’s are a simple, accurate, and cost effective ways to measure alkalinity in seawater and fresh water. Designed as a more accurate alternative to chemical test kits, these handheld colorimeters provide quick, accurate alkalinity testing results in four easy steps.

Step One – Add a sample to the included cuvette(s).

Step Two – Insert sample into the Checker®HC and press the button to zero.

Step Three – Remove sample and add reagent as stated in the manual.

Step Four – Reinsert sample and press the button to measure your results.

The contoured style of these Checker®HCs fit easily in the palm of your hand or pocket and the large LCD is easy to read. The auto shut-off feature assures the battery life will not be drained if you forget to turn it off.

HI755 (Seawater)HI775 (Fresh water)
Range0 to 300 ppm CaCO₃0 to 500 ppm CaCO₃
Resolution1 ppm1 ppm
Accuracy @ 25°C/77°F±5 ppm ±5% of reading
Light SourceLED @ 610 nm
Light Detectorsilicon photocell
Environment0 to 50°C (32 to 122°F); RH max 95% non-condensing
Battery Type(1) 1.5V AAA
Auto-offafter ten minutes of non-use
Dimensions81.5 x 61 x 37.5 mm (3.2 x 2.4 x 1.5”)
Weight64 g (2.25 oz.)
Methodcolorimetric method. The reaction causes a distinctive range of colours from yellow to green to blue to develop

Need Help?

We can advise on the correct water testing equipment for your requirements.
Please contact us on
01629 363311

we are more than happy to help.