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Measure & Test

NYOS Magnesium Reefer

NYOS Magnesium Reefer
NYOS Magnesium Reefer

High precision seawater magnesium test kit

  • simple conversion factor
  • accurate to 15 mg/l
  • precise dosing tip
  • precise color change
  • Manufacturer:Nyos
  • Item number:156154
  • Included:

    50 ml Reagent MG-1, 5 g Reagent MG-2, 50 ml Reagent MG-3, 1 Test container, 1 Green syringe 1 ml, 1 Red syringe 1 ml, 1 Black Syringe 1 ml, 1 Dropper tip, 1 Instructions for use, 1 Measuring spoon

  • Best before date:31.10.2026
17,90 €

including 19% VAT ,

Recommended retail price: 17,90 €


Water properties as close to nature are the key for every aquarium's success. However, monitoring relevant parameters in seawater is difficult due to numerous interfering ions. Therefore, test kits considering the specific characteristics of seawater are needed to analyse the water precisely.


Highly precise analyses for seawater conditions. Furthermore, they offer a highly attractive price-performance ration and make test kits in laboratory quality affordable for the standard hobby user.

Additional characteristics of our reefer test kits:
  • calibrated dropper made by a German manufacturer ensures uniform drops during all repeat tests
  • reagents are made in Germany in accordance with EN ISO 9001
  • reagents are analysed according to AAS and NIST standards
  • strict batch and quality control
  • easy to use with intuitive pictogram instructions
  • Made in Germany

NYOS® REEFER test kits allows you to achieve precise and most importantly reproducible (i.e. in repeat measurements identical) measuring results.

1. Rinse out the test container several times with aquarium water. Then add 1 ml aquarium water using the green syringe.

2. Draw up and add 1 ml reagent MG-1 using the red syringe. Briefly swirl.

3. Add 1 measuring spoon MG-2 and swirl to mix. The water sample turns pink-violet.

4. Place the dropper tip onto the black 1 ml syringe. Draw up 1 ml reagent MG-3 using the syringe. To do this, the lower edge of the black plunger ring must sit exactly on the 1 ml mark (see diagram). A small air bubble under the plunger will not interfere with the test.

5. Slowly, drop-by-drop, add reagent MG-3 while swirling (important!). Continue adding reagent MG-3 drop-wise until the solution turns completely grey or blue. The grey or blue colour must still be present after 30 seconds, if not continue adding MG-3 until the water finally turns grey or blue.

6. To determine the magnesium value in ppm, calculate how much of the syringe content was used. 1 used mark (=0.01 ml) equals 15 ppm magnesium. For this, please also see the calculation table on page 2 in the PDF file (Downloads).

Example: If the amount used in the syringe is 0.8 ml (i.e. 0.2 ml liquid remains in the syringe), the magnesium value is 1200 ppm.

Optimal value

We recommend adjusting the magnesium content to 1250 - 1350 ppm in a reef tank.

Store the test kit under cool (<25°C/77°F), dry conditions.

PDF Magnesium_Reefer_Manual
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