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The HI-713 Phosphate Checker provides an accurate solution for measuring low range phosphate within both marine and freshwater fish tanks. This digital phosphate tester has a single-button operation to measure phosphate in aquariums, providing fast information to allow you to monitor and adjust your water quality.

Hanna’s range of phosphate Checkers includes all required ranges for tank maintenance and care alongside a wide range of other key parameters.

0.00 to 2.50 ppm
Ideal for coral, salt and fresh water tanks

£72.00 (exc.VAT)
£86.40 (tax incl.)
Full Description Specification Manuals

HI-713 Low Range Phosphate Checker

The HI-713 Checker is a fast and accurate method for measuring low range phosphate within all kinds of aquariums, including reef, marine and freshwater fish tanks. This compact digital tester allows you to determine the amount of phosphate in tank water, with a single-button operation and clear, easy-to-read results on an LCD screen in ppm.

The HI-713 electronic tester covers the low range for phosphate testing in aquarium water, from 0.00-2.50 ppm. An included AAA battery is required to power this Checker, and a built-in auto-off feature after 10 minutes inactive preserves battery life for continued testing.

Why measure phosphate?

Phosphate is present in most tanks, and is typically managed using filtering, cleaning and binding chemicals to keep them within an acceptable range. Sources of phosphate include broken down or decaying food and plant matter in addition to pH and kH buffers and waste products from fish. While phosphate is not directly an issue, high levels cause algae blooms that decrease oxygen and may change the pH of the water, indirectly causing harm.

Measuring phosphate regularly is an ideal way to keep this parameter in the lowest range possible. Using a digital Checker is fast and accurate, enabling you to have results as quickly as possible to make the necessary changes to your fish tank to prevent algae growth.

How does the HI-713 work?

The HI-713 uses an adaptation of Standard Methods for the Examination of Water and Wastewater. 20th Edition, Ascorbic Acid Method. In this method, the compatible reagents that come with this Checker react with the water sample. The reaction between phosphate and the reagent causes a blue tint in the sample. This colour is then read by the Checker to provide an on-screen digital readout of phosphate levels in parts per million.

The HI-715 includes a reagents starter kit for 6 tests, so you can start testing the phosphate levels in your aquarium immediately out of the box.

Four steps to test

Step 1  1. ‘Zero’ the Checker with your vial & 10 ml water sample inside

Step 2  2. Take your vial out and add your reagent

Step 3  3. Place your vial into your Checker

Step 4  4. Press the button and read the results

Checkers vs test strips

Test strips are a popular choice for measuring phosphate within aquarium water. However, the accuracy of these tests rely on personal perception of the results, comparing the colour of the strip to determine how much phosphate is present. Hanna Checkers remove the guesswork in testing, providing a clear and accurate digital ppm result from testing, allowing you to swiftly make water condition changes to prevent algae bloom before it occurs.

Where can the HI-713 Phosphate LR Checker be used?

  • Freshwater Aquariums
  • Coral Reef Tanks
  • Saltwater Aquariums
  • Aquaculture
  • Natural Water Testing
  • Wastewater Testing
  • Agricultural Applications
  • Drinking Water Testing


  • Small, handheld design
  • Accurate to ±0.04 ppm (mg/L) ±4% of reading
  • Dedicated to a single parameter
  • Single AAA battery required for operation (included)
  • 10 minute auto power-off functionality
  • Built-in timer for timed reaction readings

Order Information:

The HI-713 Checker is supplied with 2 cuvettes and caps, Phosphate LR reagents x 6 tests (HI-713-25), 1 x 1.5V AAA battery, and an instruction manual.

Order more reagents with code HI-713-25 for the HI-713 Phosphate Low Range Checker

Safety Data Sheets

When using any form of chemical, such as Hanna reagents, it is important you download the relevant safety data sheet and make yourself aware of any precautions you should take when handling the chemical. You can access our library of safety data sheets and download a copy by following the link below.

Please note that the '-' in HI- products should be removed from all searches to find the correct information.


Read More

Range0.00 to 2.50 ppm (mg/L)
Resolution0.01 ppm (mg/L)
Precision±0.04 ppm (mg/L) ±4% of reading @ 25°C
Light SourceLED @ 525 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 2 minutes of non-use and after read
Dimensions86 x 61 x 37.5 mm (3.2 x 2.4 x 1.5”)
Weight64 g (2.25 oz.)
MethodAdaptation of Standard Methods for the Examination of water and wastewater. 20th edition, Ascorbic Acid method. The reaction between phosphate and the reagent causes a blue tint in the sample.
PLEASE NOTE:In some cases, samples may contain other parameters which may interfere with results
Interference may be caused by:Iron above 50 mg/L
Silica above 50 mg/L
Silicate above 10 mg/L
Copper above 10 mg/L
Hydrogen sulphide, arsenate, turbid sample and highly buffered samples also interfere.