Hanna Instruments

Hanna Instruments Checker Marine Ultra Low Range Phosphate Colorimeter


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The Ultra Low Range Phosphate Checker® HC (HI774) is a cost-effective way to measure phosphate in marine systems, including reef tanks. Testing for phosphates is standard practice for saltwater aquariums and provides valuable insight into your reef tank’s water chemistry to help ensure long-term coral health.

Phosphates are one of the many forms of phosphorus compounds found in marine waters. Excessive phosphate levels can prevent calcification, skeletal formation, and growth of many coral species, particularly those referred to as SPS or small-polyp stony. In addition, high phosphate levels can cause nuisance algae growth in your reef tank. This can become problematic because algae often out competes sessile organisms for light, nutrients, and space, jeopardizing long term coral health in your reef.


  • Accurate digital test kit for reef tank phosphate levels
  • Easier to use and more accurate than chemical test kits
  • Dedicated to a single parameter
  • Small size, big convenience
  • Ideal for: Aquariums, Environmental, Aquaculture, Water Quality
  • Removes subject color interpretations from testing results
  • Simple, one-button design makes getting your results easy


Range0.00 to 0.90 ppm
Resolution0.01 ppm
Accuracy 77° F / 25° C±0.02 ppm ±5% of reading
Light SourceLED @ 525 nm
Light DetectorSilicon photocell
MethodAdaptation of the Standard Methods for the Examination of Water and Wastewater, 20th Ed., Ascorbic-Acid Method
Environment32 to 122°F (0 to 50°C); RH max 95% non-condensing 
Battery Type1 x 1.5V AAA
Auto-offafter 7 minutes of non-use and 2 minutes after reading
Dimensions3.4" x 2.4" x 1.5" (86.0 x 61.0 x 37.5 mm)
Weight64 g (2.25 oz.)
Includes(2) sample cuvettes with caps, phosphate ULR reagent starter kit for 10 tests, batteries, instructions, and quick start guide
Warranty1 year limited warranty

Hanna Phosphate Checker Comparison:

Checker Model:

Ultra Low Range Phosphate Colorimeter - HI774

Low Range Phosphate Colorimeter - HI713

Range: 0.00 to 0.90 ppm 0.00 to 2.50 ppm (mg/L)
Accuracy (@25°C/77°F): ±0.02 ppm ±5% of reading ±0.04 ppm ±4% of reading
Resolution: 0.01 ppm 0.01 ppm
Readout: Parts per million phosphate Parts per million phosphate
Auto off: after 7 minutes of non-use and 2 minutes after reading after 3 minutes of non-use and 2 minutes after reading
Starter reagents: phosphate ULR reagent starter kit for 10 tests (HI774-0) phosphate LR reagent starter kit for 6 tests (HI713-0)
Refill: HI774-25 HI713-25

Manufacturer Info

Hanna Instruments USA Aquarium Supplies
Hanna Instruments is a leading manufacturer of analytical aquarium instrumentation. They were founded in 1978 and are headquartered in Woonsocket, Rhode Island. When Hanna introduced pH Electronic Paper in 1986 it literally revolutionized the world of testing by allowing millions of people in various industries to test for pH in a simple, accurate and affordable way. Hanna employees are constantly challenging themselves to improve on existing technology and to invent new testing techniques with the common goal to simplify analytical testing. This applies not only to instrumentation, but also to sensors development, reagents and chemicals. Hanna also believes in controlling the quality of their products from inception to delivery so they manufacture everything themselves, from meters and electrodes to chemical reagents and buffer solutions.

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