HagenKB

Magnesium Measurement - Saltwater

Which test kit will measure Magnesium in saltwater?

Which test kit will measure Magnesium in saltwater?
Use the present Hardness test kit in the following procedure to obtain a measurement of the magnesium level in salt water.

1. Do a modified Hardness test for Saltwater

Saltwater 5 %

Measure 5 ml of saltwater from the aquarium in question and dilute with 95 ml of demineralized, distilled or reverse osmosis treated water.

Pour 5 ml of this 5 % solution into the test tube provided with the Hagen Hardness Test Kit (Art. # A-7830).

Use the GH test kit directions, however in the calculation replace the factor of 20 with a factor of 400. This provides the amount for A in the calculation below.

2.Analyse for calcium

Use a sample of standard saltwater from the aquarium (not a diluted one)

Follow the directions according to the leaflet. The result of the test should be multiplied by 2.5 to provide the proper amount for B in the calculation below.

3.Use the calculation included on the back of the Calcium booklet to determine the actual magnesium concentration.

A - B = Magnesium mg/L
4.118

A - General Hardness measurement

B - Calcium result times 2.5 (calcium result X 2.5)

Normal magnesium levels of saltwater should be between 1300 and 1400 mg/L.

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