The HI781 Marine Nitrate Low Range Colorimeter is designed to accurately determine low range nitrate levels in saltwater aquariums and marine applications.
With a digital read out, there is no more struggling to determine colors visually.
The HI781 Checker ® HC is a simple, accurate, and cost-effective way to measure nitrate from 0.00 to 5.00 ppm (as NO3–) in your saltwater aquarium.
Nitrate is a by-product of the Nitrogen cycle. Excessive amounts of nitrates in a reef aquarium can promote the growth of undesirable organisms including algae and dinoflagellates while insufficient amounts can lead to starvation in which SPS and other corals will show signs including the loss of color and paleness.
The HI781 Nitrate Checker HC is a handheld colorimeter that uses the Beer-Lambert principle to determine the concentration of nitrate colorimetrically. The HI781 is designed specifically to measure low levels of nitrate in a saltwater aquarium.
Sepcifications:
Range : 0.00 to 5.00 ppm NO3-
Resolution : 0.01 ppm
Accuracy @ 25°C : ± 0.25 ppm ±2% of reading
Light Source : LED @ 525m
Light Detector : silicon photocell
Battery Type : (1) 1.5V AAA
Auto-off : after 10 minutes of non-use
Environment : 0 to 50°C ; RH max 95% non-condensing
Dimensions : 86.0 x 61.0 x 37.5 mm
Weight : 64 g
Calibration Set : HI781-11 Not included
Warranty : 1 year
What's inculded
1x HI781 Checker®HC 
2x sample cuvettes with caps
1x aHI-781-25 reagent (25 tests)
25x Filter paper 
1x Filter holder 
1x Mixing vial and cap 
1x 5 mL syringe with tip 
1x 10 mL syringe 
1x 1 mL graduated syringe 
1xx Plastic refilling pipette 
1x 16 gauge blunt needle 
1x batteries
1x instructions, and quick start guide.