Hanna Instruments

Scientific Equipment

Safety Data Sheets

SDS search & quick download

Free Delivery on Web Orders

Most of mainland GB for orders over £50. Other charges may apply - see more

Hanna Care

We take the long view, looking after existing customers as much as delighting new ones!

Certificates of Analysis

Download a copy of the certificate of analysis for your solution

HI-721 High Range Iron Handheld Colorimeter - Checker®HC

HI-721 High Range Iron Handheld Colorimeter - Checker®HC

Hanna HI-721 High Range Iron Handheld Colorimeter - Checker®HC

HI-721 High Range Iron Handheld Colorimeter - Checker®HC

0.00 to 5.00 ppm
Ideal for irrigation water
In Stock
£58.00 (exc. VAT) £69.60 (inc. VAT)

The HI-721 pocket checker for iron gives quick, accurate results at the price of a chemical test kit.

Checker®HC is supplied with reagents for 6 tests. Use code HI-721-25 (25 tests) for future purchases.

Ideal for:

  • Swimming pools and spas
  • Aquaculture - marine, salt and fresh water
  • Quality control and ground water monitoring
  • Agriculture and small holdings

HI-721 High Range Iron Handheld Colorimeter - Checker®HC information

Hanna's extended description

HI-721 High Range Iron Handheld Colorimeter - Checker®HC

About 6.3% of the earth crust is made of iron with 43% of this amount held in the soil. As a result, iron is naturally present in most water supplies.

Left in the water, iron will not only stain pipework and swimming pool surfaces, or poison aquatic life, it will also affect the water taste and cause problems with animal feed lines.

Testing should therefore form an important part of any water monitoring process - particularly if you are checking your pool, watching the quality of water in your fish tank or needing to monitor water run-off.

Key features

  • Accurate and easy to use
  • Phenanthroline method
  • Accuracy ±0.04 mg/L (ppm)
  • 0.01 mg/L (ppm) resolution
  • Designed to work with Hanna reagents
  • Large easy to read digits
  • Auto shut-off
  • Fits into the palm of your hand

Four steps. One click. Instant Readout.

1. ‘Zero’ the Checker®HC with your vial inside

2. Place a 10ml water sample into the vial and add your reagent

3. Place your vial into your Checker®HC

4. Press the button and read the results

Battery powered – Allows use away from a power source. Batteries are included with all battery operated products.

Use calibration check set HI-721-11 with the HI-721 High Range Iron Handheld Colorimeter - Checker®HC.

Use reagent HI-721-25 with the HI-721 High Range Iron Handheld Colorimeter - Checker®HC, 25 tests.


Specifications list


Range 0.00 to 5.00 ppm (mg/L)
Resolution 0.01 ppm (mg/L)
Precision 2% of reading ±0.04 ppm (mg/L) @ 25°C
Light Source LED @ 525 nm
Light Detector Silicon photocell
Environment 0 to 50°C (32 to 122°F); RH max 95% non-condensing
Battery Type (1) 1.5V AAA
Auto-off After 2 minutes of non-use and after read
Dimensions 81.5 x 61 x 37.5 mm (3.2 x 2.4 x 1.5”)
Weight 64 g (2.25 oz.)
Method Adaptation of EPA Phenantroline method 315B, for natural and treated waters.
PLEASE NOTE: In some cases, samples may contain other parameters which may interfere with results
Interferences may be caused by: Alkalinity: above 2,000 mg/L (as CaCO3). May slow down colour development (negative error). To resolve this, neutralise the sample with diluted HCl.
Calcium (Ca2+): above 10,000 mg/L as CaCO3
Copper (Cu2+): does not interfere: reagent contains a masking agent.
Magnesium (Mg2+): above 100,000 mg/L as CaCO3
Molybdate Molybdenum: above 25 mg/L (as Mo-MoO4) (positive error) Sample containing up to 50 mg/L Mo-MoO4 may be measured if a reading is taken after 1 minute instead of 3 minutes.
High Iron concentrations up to 200 mg/L do not inhibit colour development; above 200 mg/L colour development may be inhibited.
High sulphide concentrations (S2-): high sulphide concentrations may interfere. To reduce sulphide: acidify the sample and boil for about 20 minutes, neutralise and adjust volume before measurements.
Silica (SiO2): above 175 mg/L (as SiO2). May slow down colour development (negative error)

Questions & Answers

Got a question to ask? Use this form to submit your question.
Question will be displayed after moderation.
Name* Product Question*
No questions yet?
Don 't be shy, be the first to ask.