Blister pack for the JBL PROAQUATEST Fe refill, one dropper bottle of iron reagent

Reagent refill for iron Fe test

Name: Reagent refill for iron Fe test
Brand: Hardy Dewerse
SKU: J2411700
Price: 10.5 EUR
Availability: InStock

10,50 €

3,50 € × 3 with no fees Klarna.

This dropper bottle is the reagent for the iron test, giving approximately 50 measurements. It colours only the iron remaining in solution — the iron your plants can actually take up.

The reading ranges from 0.02 to 1.5 mg/L across nine steps. The two test tubes, the syringe, the comparator block, and the colour chart from your test kit remain in use.

Ref. J2411700·Reagent refill

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The summary

What it measures: dissolved iron, not iron that has precipitated to the bottom.
What the box contains: 1 dropper bottle of Fe reagent.
The reading range: from 0.02 to 1.5 mg/L, across nine colour steps.
What you're aiming for: 0.1 to 0.2 mg/L in a planted water system.
The step not to skip: rinse the test tubes several times before you begin.
Refill or complete kit: the refill is sufficient if you have kept the comparator block and colour chart from the original kit.

The reagent bottle alone, approximately 50 measurements, from 0.02 to 1.5 mg/L of dissolved iron.

Water may have received a great deal of iron yet contain almost none in an absorbable form, because iron that is not protected by a chelate precipitates out. This dropper bottle is the reagent only for the drop-based iron test, and it colours only the portion remaining in solution, the part your roots can actually take up, for approximately 50 measurements.

🌿 Iron that is actually available

Iron is consumed continuously and remains stable only for a limited time in water, even when bound to a chelate. In a planted aquarium, a level of 0.1 to 0.2 mg/L is already sufficient for healthy growth, with a heavily planted tank potentially reaching 0.6 mg/L, while in saltwater the level stays below 0.05 mg/L. The vegetable crops in an aquaponic system are more demanding, and the FAO guide on aquaponics targets around 2 mg/L: to read a value above 1.5 mg/L, at the top end of the colour chart, dilute the sample in demineralised water and multiply the reading by the dilution factor. As tap water contains virtually none, your measurement tells you when to add more, and a value that stays low immediately after dosing indicates a chelate unsuited to your pH rather than an insufficient dose.

Nine gradations

The colour chart runs from 0.02 to 1.5 mg/L, with graduations that become closer together at the lower end of the scale, where dosing decisions are made.

10 minutes

5 drops into just one of the two 5 ml test tubes, then 10 minutes' rest before reading in the block.

Rinse the test tubes after an ammonium test

Traces of ammonium reagent left in a test tube will give a higher iron reading than the actual value. Rinse both test tubes several times with the water being tested before you start, and set them aside specifically for this test if possible, especially if you are measuring ammonium on the same day.

🍃 Yellow buds and chelates

In aquaponics, fish feed alone rarely covers the iron requirements of your crops, so supplementation is almost always done using a chelate chosen to match the pH: DTPA suits water close to neutral, EDDHA suits hard water. A deficiency shows up first on buds and young leaves, which take on a yellowish, glassy appearance. The guide on iron deficiency in aquaponics helps you distinguish it from a magnesium deficiency, which the magnesium test resolves with a single measurement.

DTPA chelate for water close to neutral pH

Take the DTPA 11% chelated iron with this refill if your pH stays close to neutral, as this chelate keeps iron available up to pH 7.5 without discolouring the water. Test before dosing, then again a few days later, and the difference between the two readings will tell you the right dose for your system.

💧 A dropper bottle

The reagent is classified Warning, with hazard statements H302, H317, and H319: harmful if swallowed, it may cause a skin allergy and severe eye irritation. Wear gloves if you have sensitive skin, and store the bottle sealed, in a dry place at room temperature, in its original packaging. At the recommended frequency, one measurement after installation and then one per week, the 50 tests cover approximately one year of monitoring, and you add an extra measurement whenever green algae appear or your plants' growth slows down.

Technical specifications

What the refill contains

Contents: 1 dropper bottleFe reagent — hold vertical, tip dry and bubble-free
Measurements: Approximately 505 drops per measurement, for the same volume of reagent as in the original kit
Colour chart range: 0.02 to 1.5 mg/LNine graduations: 0.02, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 and 1.5
Target values: 0.1 to 0.2 mg/L in a planted water environmentUp to 0.05 mg/L only in seawater. A heavily planted tank can tolerate up to 0.6 mg/L
Manufacturer's reference: JBL 2411700, PROAQUATEST rangeNot to be confused with 2411600, which is the complete test kit
Hazard classification: Please note, single bottleHazard statements H302, H317 and H319. Store in a dry place, at room temperature, lid firmly closed

To budget for separately

Glassware and syringe: Those from the iron testTwo are needed: one receives the reagent, the other remains untreated and serves as a control
Comparator block and colour chart: Those from the iron testThe block slides along the colour chart until the two shades match.

In the box

1 Fe reagent dropper bottle

Reference, EAN code, contents, protocol, number of tests, and hazard statements taken from the JBL data sheet and instruction manual on 07/10/2026. The range and nine-step scale are taken from a photograph of the colour card supplied. Dilution: JBL FAQ.

The bottle alone, or the iron kit?

A single reagent on both sides, and the same number of measurements. What changes is the glassware and the reading optics, which last for years.

Iron is read at the bottom of the scale The first steps on the colour chart read 0.02 and then 0.05 mg/L. Refilling therefore requires a colour chart that still shows clear contrast, plus the block that holds both test tubes.

	Reagent bottles (bottles)	Possible readings (measurements)	Screw-top glass test tubes	Graduated syringe for 5 ml	Grey comparator block	Nine-step colour chart	Price
Recommended Reagent refill for iron Fe testYour choice	1 bottles	50 measurements	No	No	No	No	10,50 €
Iron Fe water test in dropsYour choice	1 bottles	50 measurements	Yes	Yes	Yes	Yes	16,50 €

Reagent refill for iron Fe testRecommended

What gets used up

Reagent bottles (bottles)1 bottles

Possible readings (measurements)50 measurements

What keeps well

Screw-top glass test tubesNo

Graduated syringe for 5 mlNo

Grey comparator blockNo

Nine-step colour chartNo

Budget

Iron Fe water test in drops

What gets used up

Reagent bottles (bottles)1 bottles

Possible readings (measurements)50 measurements

What keeps well

Screw-top glass test tubesYes

Graduated syringe for 5 mlYes

Grey comparator blockYes

Nine-step colour chartYes

Budget

Contents of both columns taken from the supplier's data sheet and instruction leaflet, on 05/09/2026.

Estimate your
delivery time

Package weight 0.08 kg, dispatched to a collection point or to your home address, your choice at checkout. The bottle is sent in its original packaging. The exact shipping cost is shown in the basket.

Frequently asked questions

6 questions

6 key questions

Why is iron that has settled to the bottom not counted?

Which chelate should I choose based on my pH?

Your water	The stable chelate
Acidic	EDTA
Neutral	DTPA
Hard (calcareous)	EDDHA

A poorly chosen chelate releases its iron, which precipitates immediately. Doses are applied one after another without the measured value rising — that's the sign that you need to switch form rather than increase the dose. Chelated iron DTPA 11% covers the most common case.

Why rinse the test tubes before this test?

My reading exceeds 1.5 mg/L — what should I do?

Can an iron deficiency be confused with a magnesium deficiency?

What precautions should be taken with this reagent?

It is classified Warning, with the hazard statements H302, H317, and H319: harmful if swallowed, it may cause a skin allergy and severe eye irritation.

Wear gloves if your skin is sensitive, keep the bottle out of children's reach despite its child-resistant cap, and rinse thoroughly with water if any splashes into the eye. An empty bottle should be taken to a recycling centre with household chemical waste.

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Reagent refill for iron Fe test

The summary