HI-774-25 Reagent – ULR Phosphate


Reagent Refill for Hanna ULR Phosphate checker HC Colorimeter.
Pack contains 25 Pre-measured refill sachets (25 tests)

3 in stock


HI-774-25 Reagent – ULR Phosphate

HI-774-25 Reagent refills are meant for use with the Hanna ULR Phosphate checker colorimeter (HI774). This is a very accurate way of testing phosphate levels for either marine or freshwater aquariums. ULR stands for ‘ultra low range’. These reagents are designed to be used with samples that have an expected range of 0.00 to 0.90 ppm phosphate. If you would like a wider range test kit, instead look at the Hanna LR Phosphate checker (HI713). The later tests both marine or freshwater aquariums with levels between 0.00 to 2.5ppm.


These reagents follow the Ascorbic Acid Method. The reaction between phosphate and the reagent causes a blue tint in the sample. This will then be read by your Hanna ULR phosphate checker. The Hanna checker is a much more accurate way of checking water samples compared to going with your eyesight. This is because in different light levels samples can look a little different and can be hard to gauge against the colour charts given in standard test kits.


This HI-774-25 Reagent – ULR Phosphate pack contains 25 prefilled high quality reagent sachets ensuring easy and accurate results with every test.



Algae Control

Historically, phosphate has been seen as a bit of a nuisance. The cause of a lot of problems when it comes to keeping aquariums. Nowadays, due to massive improvements in both equipment and knowledge we have a much better understanding of the role phosphate plays within the closed system of a fish tank.

High levels of phosphate can cause serious algae issues and can also have a detrimental effect on other livestock. However, we now know, especially for marine reef aquariums or freshwater planted tanks, that reducing levels until there is no phosphate at all can cause its own issues. This is especially noticeable when it comes to coral growth and health and has also been attributed to issues with pests such as dinoflagellates.

In natural seawater, phosphate is very low to almost non-existent, but the ocean is far more complicated than the closed system of an aquarium!

For reef aquaria and especially SPS coral care we recommend maintaining a Po4 level between 0.05 and 0.1ppm.

For fish only systems we would recommend a Po4 no higher than 0.5.

The Hanna Checker – Phosphate ULR is perfect for checking phosphates within this range and ensuring the levels don’t drop too low.

Four steps, one click instant readout:

  • Add a control sample
  • Add a sample with the reagent
  • Set the timer by holding the button down
  • Read results



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