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Hanna Instruments Phosphate Checker (HI774) - Ultra Low Range


Item #: HN7741

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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
  • Includes Phosphate ULR Reagent Starter Kit for 10 Tests (HI774-0) [Additional tests available for purchase HERE]

ULR Phosphate Checker Specifications:

Range: 0.00 to 0.90 ppm
Resolution: 0.01 ppm
Accuracy 77° F / 25° C: ±0.02 ppm ±5% of reading
Light Source: LED @ 525 nm
Light Detector: Silicon photocell
Method: Adaptation of the Standard Methods for the Examination of Water and Wastewater, 20th Ed., Ascorbic-Acid Method
Environment: 32 to 122°F (0 to 50°C); RH max 95% non-condensing
Battery Type: 1 x 1.5V AAA
Auto-off: after 7 minutes of non-use and 2 minutes after reading
Dimensions: 3.4" x 2.4" x 1.5" (86.0 x 61.0 x 37.5 mm)
Weight: 64 g (2.25 oz.)
Includes: (2) sample cuvettes with caps, phosphate ULR reagent starter kit for 10 tests, batteries, instructions, and quick start guide
Warranty: 1 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 information

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.

5 Stars


Reviewed on
January 30, 2021

Yes, I would recommend this.

Best Phosphate Reading

Pros: fast, accurate

Cons: None

This is the best investment i have made. Tried other test kits but it was very difficult to distinguish between low and ultra low. This gives an actual value which is peace of mind to me. With an actual value you can determine how much GFO you need to bring it down. No guessing.

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Reviewed on
November 30, 2020

Yes, I would recommend this.

Very accurate

Pros: Easy

Cons: None

Makes testing phosphates a piece of cake

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Reviewed on
July 26, 2020

No, I would not recommend this.


Pros: measures consistently since it is a digital device

Cons: can't keep it on long enough to take the measurement

The product works great with one exception. In order to run a test here are the steps 1) test tank water, 2) add reagents 3) shake the vial for 2 minutes 4) wait 3 minutes 5) test water with reagents. For those doing the math, steps 2-4 can take ~7 mins or more. However, the device is designed to power off after 7 mins. So you have to RACE through steps 2-5 before the unit shuts off. IF it does shut off, you have to repeat the entire process since you lose the results from step 1. This is very annoying as it is time-consuming, wastes reagent packets, and makes this unit almost unusable.

For completeness, they do have an auto 3min counter feature, however, I don't use that feature for two reasons 1) if I forget to hold the button to engage this counter, I have to start everything over. And I tend to forget since my Alk Checker doesn't require this. Also, if I do successfully use the feature, if I don't read the results right after the 3 mins are up I will lose the results since the unit auto powers off quickly after the reading. So don't look away or get restricted.

Overall, these usability issues are really easy to fix and it is a shame they exist. All they would have to do is extend the time out. Their other checkers don't have such a short time out so I don't know why they have one on this unit.

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Reviewed on
July 13, 2020

Yes, I would recommend this.

Hannah Phosphate checker

Pros: Accurate

Cons: Prepare the reagent sack so you can get the contents into the vial in time

Fast results, easy to use

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Reviewed on
July 03, 2020

Yes, I would recommend this.

I hate testing

Pros: No guessing. Easy to use

Cons: None

I really do hate testing water because of all of the guess work of trying to match colors, This tester removes all the guessing. Love it

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Reviewed on
July 02, 2020

Yes, I would recommend this.

Easy and quick Test Results

Pros: Easy to use

Cons: Only a few reagents included

Great product to easily test phosphate levels in the tank. I would reccomend purchasing a box of reagents with this.

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Reviewed on
June 17, 2020

Yes, I would recommend this.

very convenient

I like the digital readout. I really have trouble matching colors. I don't like pouring powder from a packet because I can see there is powder stuck to the packet. I wonder about the accuracy and whether results are consistent.

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Reviewed on
May 28, 2020

Yes, I would recommend this.


Great product helping keeping stability.. fast shipping

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Reviewed on
April 30, 2020

Yes, I would recommend this.

Works Great

Pros: Easy to use

Cons: Wish it came with more test packets.

I feel like a lab tech using this device. :) Very easy to use and fast.

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Reviewed on
April 27, 2020

Yes, I would recommend this.

love it

so nice to not have to match colors that never seem to really match. love all the hanna checkers i have.

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