Blister pack for the JBL PROAQUATEST Mg freshwater refill, four bottles including two of reagent 1

The three bottles of JBL ProAquaTest magnesium Mg freshwater reagents supplied in the refill, on a white background

Reagent refill for magnesium test

Name: Reagent refill for magnesium test
Brand: JBL
SKU: J2414300
Price: 21.0 AUD
Availability: InStock

$21.00

These four bottles, two of which are reagent 1, are the reagents for the magnesium test, good for about 60 tests. They measure magnesium alone, whereas total hardness adds it to calcium.

The colour chart runs from 0 to over 10 mg/L across eight fields, and the colour, which develops in 1 minute, can be read within the following 15 minutes. You keep the two test tubes, the syringe, the comparator block and the colour chart from your kit.

Ref. J2414300·Reagent refill

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The summary

Reagent 2, corrosive: nothing from the tested sample goes back into the tank, since these reagents never go into the fish water.
What's in the box: 4 bottles, 2 of them reagent 1.
How many tests: about 60, the same count as the original kit.
What you're aiming for: 5 to 10 mg/L for good plant growth.
The constraint to know about: the colour stays readable for only a quarter of an hour.
Four bottles or the kit: the refill is enough if you have kept the kit's eight-field colour chart and comparator block.

The three reagents for the magnesium test, approximately 60 measurements, in freshwater.

With its 4 bottles, 2 of them reagent 1, this refill for the magnesium drop test gives around 60 measurements in fresh water, read on the colour chart in the kit. For your plants, aim for 5 to 10 mg/L. Reagent 2 is corrosive, and none of the three ever goes into the fish's water.

Magnesium is part of total hardness, but the GH titration lumps it in with calcium. These four bottles, two of them reagent 1, are the reagents alone for the freshwater magnesium test, and they measure it separately, for around 60 measurements.

🕒 A three-step measurement

Fill two 10 ml test tubes, add the three reagents to one of them, then wait 1 minute for the colour to develop. The shade then stays stable for 15 minutes at most, and a later reading may give a different value. So prepare the colour chart and the comparator block before testing, and read straight away; if you are interrupted, repeat the test rather than reading a test tube that has been left standing.

Seven, three, then two drops, in that order

The three reagents are not dosed in the same quantities: add 7 drops of reagent 1, then 3 drops of reagent 2, then 2 drops of reagent 3, mixing between each addition. One drop too many on any of the bottles throws off the whole reading, so keep the instructions open until the order is second nature.

Tap water, even very hard water, often contains too little magnesium for aquatic plants. The colour chart has eight fields, 0, 1, 2, 3, 6, 8, 10 and over 10 mg/L, closer together at the bottom of the scale, and you should aim for a level of 5 to 10 mg/L for good growth. This test is intended for fresh water only, since sea water contains about 1,000 mg/L.

Correcting magnesium with Epsom salt, gram by gram

If your reading stays below 5 mg/L, Epsom salt, a magnesium sulphate, raises the level without affecting carbonates. One gram dissolved in 10 litres raises it by about 10 mg/L, so add it in small amounts and measure again before each new addition.

🔎 Iron or magnesium on the leaf

A magnesium deficiency shows up first on the older leaves, at the bottom of the stem, as yellowish discolouration between veins that stay green, sometimes with curled leaves, because the plant redistributes this mobile element to its young shoots. An iron deficiency produces the same yellowing between the veins, but on the leaves at the top, since iron is not redistributed. So measure magnesium with these bottles and iron with the iron test before correcting anything, so that the measurement confirms what the position of the leaves suggests. The guide to recognising deficiencies in aquaponics compares the two signatures.

📋 Storage and replacement

Only reagent 2 is classified, with the signal word Danger and the hazard statement H314, since it contains sodium hydroxide. Store the bottles with their caps on, in a dry place at room temperature and in their original packaging, and open the second bottle of reagent 1 only when the first is empty, since each measurement uses 7 drops of it against 3 and 2 for the other two. At the start, one measurement a day lets you work out how much your plants consume, after which you space the checks out, so the 60 measurements are mostly used up during the first few weeks.

The bottles are used with the test tubes, the syringe, the block and the eight-field colour chart from your magnesium drop test. Order the refill before a start-up, a period when testing becomes daily, and pour the tested water down the sink: reagent 2 never goes into the fish's water.

Technical specifications

What the refill contains

Contents: 4 bottles, including 2 of reagent 1Reagents 1, 2 and 3, with child-resistant caps
Readings: Around 607, 3 then 2 drops per measurement
Manufacturer's reference: JBL 2414300, PROAQUATEST rangeNot to be confused with 2414200, which is the complete kit
Matching test: Magnesium Mg test, freshwaterRef. 2414200, with its eight-field colour chart and its grey block

Reading magnesium

The colour chart fields: 0, 1, 2, 3, 6, 8, 10 and over 10Eight values in mg/L, packed into the low end of the scale so you can read low levels finely
Target values: 5 to 10 mg/LRange for good growth of aquatic plants. Freshwater only

Hazard labelling

Signal word: DangerReagent 2 only, reagents 1 and 3 not sorted
Pictograms: Corrosive, GHS05
Hazard statements: H314Causes skin burns and eye damage
Precautionary statements: P101, P102, P303+P361+P353, P305+P351+P338, P501
Precautions: Sink, ventilated room, out of reachSodium hydroxide declared
Storage: Dry, at room temperatureSecond bottle of reagent 1, opened once the first is empty

To allow for in addition

Glassware, syringe and block: Those from the magnesium testTwo test tubes side by side, one treated and one with clear water, held by the grey block
Enough to correct: Epsom salt, magnesium sulphate1 gram in 10 litres raises magnesium by about 10 mg/L

6 further specifications are available in the detailed view.

In the box

4 reagent bottles, including 2 of reagent 1, with child-resistant caps

Manufacturer's values (Mg test instructions, safety data sheets and FAQ). The range of 0 to 10 mg/L and the eight fields are those of the colour chart supplied with the test. Dilution: manufacturer's FAQ.

Manufacturer and product safety

Manufacturer: JBL GmbH & Co. KG
Postal address: Dieselstraße 3, 67141 Neuhofen, Allemagne
Contact: info@jbl.de
Website: www.jbl.de

Information provided under Regulation (EU) 2023/988 on general product safety.

Four bottles, or the magnesium kit?

The same three reagents and the same number of tests are found on both sides, with the refill containing a second bottle of reagent 1. The difference lies in the eight-field colour chart and the glassware that goes with it.

Eight fields, and 15 minutes to read them The colour stays stable for only a quarter of an hour, so everything must be ready and legible before you begin. A faded colour chart makes the reading uncertain.

	Reagent bottles (bottles)	Possible tests (tests)	Glass test tubes with screw caps	Graduated sampling syringe	Laboratory comparator block	Eight-field colour chart	Price
Recommended Reagent refill for magnesium testYour choice	4 bottles	60 tests	No	No	No	No	$21.00
Magnesium Mg water test in drops, freshwaterYour choice	3 bottles	60 tests	Yes	Yes	Yes	Yes	$33.00

Reagent refill for magnesium testRecommended

What runs out

Reagent bottles (bottles)4 bottles

Possible tests (tests)60 tests

What keeps

Glass test tubes with screw capsNo

Graduated sampling syringeNo

Laboratory comparator blockNo

Eight-field colour chartNo

Budget

Magnesium Mg water test in drops, freshwater

What runs out

Reagent bottles (bottles)3 bottles

Possible tests (tests)60 tests

What keeps

Glass test tubes with screw capsYes

Graduated sampling syringeYes

Laboratory comparator blockYes

Eight-field colour chartYes

Budget

Contents of the two boxes, taken from the instructions and the data sheet for the magnesium test.

Estimate your
delivery time

A 0.08 kg parcel, dispatched within 48 hours by Colissimo or Chronopost home delivery, as you choose at checkout. The four bottles are sent in their original packaging. The exact shipping cost is shown in your basket. Once unsealed, this product cannot be returned under the right of withdrawal (article L221-28, 5° of the French Consumer Code), for reasons of hygiene and health protection.

Frequently asked questions

6 questions

6 key questions

Why measure magnesium when I already have the GH?

Why measure every day at start-up?

How do you read beyond the last field, above 10 mg/L?

How do I raise low magnesium?

Is this test suitable for seawater?

Why two bottles of reagent 1?

Because each test uses 7 drops, against 3 drops of reagent 2 and 2 drops of reagent 3.

The refill therefore contains two bottles of the first reagent for just one of each of the other two. Open the second when the first is empty, and never pour the contents of one bottle into another.

All three reagents stay out of the tank: the tested sample goes down the sink, never into the fish water.

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Reagent refill for magnesium test

The summary