Blister pack of the reagent refill for the nitrite NO2 test, two bottles visible, on a white background

The two reagent bottles numbered 1 and 2, the only contents of the refill

Reagent refill for NO2 nitrite test

Name: Reagent refill for NO2 nitrite test
Brand: JBL
SKU: J2412400
Price: 9.0 USD
Availability: InStock

$9.00

This refill contains the two reagent bottles of the NO2 nitrite test, numbered 1 and 2, for about 50 tests. The chemistry and the number of tests are those of the original kit.

Nitrite is the parameter you will test most regularly, daily while the system is filling and cycling and then weekly. You reuse the glassware, the syringe and the colour chart from your nitrite test, which last for years.

Ref. J2412400·Reagent refill

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The summary

What the box contains: 2 reagent bottles numbered 1 and 2.
What it measures: nitrite NO2, the intermediate step between ammonium and nitrate.
How many tests: around 50, as many as the original kit.
How often: one test a day for the first 3 weeks, then one a week.
Refill or complete kit: the chemistry is identical, only the accessories differ.
Two classified bottles: reagent 1 is corrosive; neither one ever goes into the fish water.

NO2 1 and NO2 2 reagents, approximately 50 tests, for aquarium, pond and aquaponics

This refill contains reagents NO2 1 and NO2 2 for the nitrite drop test, enough for about 50 measurements from 0.025 to 1 mg/L, to be used with your test tubes, block and colour chart. Plan on one measurement a day at start-up, then one a week. Reagent bottle 1 is corrosive and must never go into the fish water.

This two-bottle refill lets you keep monitoring nitrite, which is the parameter most often measured in living water. Written NO2, it is the intermediate stage of the nitrogen cycle: bacteria convert the ammonium from waste into nitrite, which a second family then converts into nitrate. Until this second family is established, nitrite accumulates and becomes toxic to your fish. Its level rises when a new tank is filled, after a filter failure, or after overly thorough rinsing of the filter media.

💧 How to read a measurement

You draw 5 ml of water into each of the two test tubes. One receives 5 drops of each reagent, while the other keeps the untreated water and serves as a colour reference. After 5 minutes, the colour is fully developed and is compared with the colour chart, with the two tubes side by side in the grey comparator block. If your water is cold, leave the sample for about 2 hours at room temperature before measuring, as the colour then develops late.

🌿 Nitrite in aquaponics

In aquaponics, your fish and your plants share the same water, and the bacterial colony in the filter links the two. Nitrite is the indicator of that colony, so as long as it remains measurable, some of the nitrogen has not yet reached the nitrate stage, the form your plants absorb. The recommended rhythm is one test per day for the first 3 weeks of new fresh water, then one per week. At that rate, this first period uses 21 tests, and the following 29 still leave you 29 weeks of weekly monitoring. The guide to the nitrogen cycle in aquaponics explains these 3 weeks in detail.

A pale shade indicates deteriorated reagents

A paler shade than usual on water that hasn't changed points to deteriorated reagents, not cleaner water: the value read is then too low, and a nitrite spike can go unnoticed. Reagent 1 also carries the Danger signal word, with H314, causes severe skin burns and eye damage. Hold the bottle vertically, nozzle pointing down, and store the box out of the reach of children.

Take back the bottles rather than the kit

Only the reagents run out, whereas the glassware, the syringe, the comparator block and the colour chart of your nitrite test last for years. Only buy the complete kit again if the colour chart is stained or faded, or if a test tube is broken or scratched, since the chart is what translates colour into a value. During cycling, the ammonium refill runs down at the same rate and is best ordered at the same time.

The right time to order it is when you know consumption is about to pick up, before the bottle runs empty. A tank start-up, a spring restart on a pond or the arrival of a batch of fish each herald a series of daily measurements. A gap in monitoring would otherwise fall at the very moment when the level can vary from one day to the next and become toxic to your fish.

📦 Contents and storage

You receive two reagent bottles with child-resistant caps, numbered 1 and 2, for around 50 tests. Screw the caps back on tightly and store the box somewhere dry, in its original packaging and away from direct light. Keep the bottles at room temperature, between 20 and 25 °C, and never in the cold, since cold reagents slow the development of the colour.

In their original sealed bottles, the reagents keep for 3 years; the expiry date and batch number are printed underneath the packaging, and that date no longer applies once the bottle has been opened, because air degrades the reagent. After each test, the dosed test tube is emptied down the sink: neither reagent 1 nor reagent 2 ever goes into the fish water.

Technical specifications

What the refill contains

Contents: 2 reagent bottlesReagents NO2 1 and NO2 2, numbered on the label
Readings: Around 50Same volume of reagent as in the original kit
Manufacturer's reference: JBL 2412400, PROAQUATEST rangeNot to be confused with reference 2412300, the complete test with its accessories.
Matching test: Nitrite NO2 test, ref. 2412300The refill is only used with the glassware, syringe, comparator block and colour chart of this test

Testing frequency

Frequency at start-up: 1 measurement per day, 3 weeksOn a new freshwater tank. Once a week on a new marine tank.
Frequency during maintenance: 1 measurement per weekPlus one extra measurement after any illness or mortality.
Dose per test: 5 drops of each reagentOn 5 ml of water, in only one of the two test tubes, the other serving as a colour reference
Time per test: About 7 minutesSix steps, including a 5-minute wait until the colour is fully developed

Hazard labelling

Signal word: DangerReagent 1 Danger, reagent 2 Warning
Pictograms: Corrosion, flame, exclamation mark
Hazard statements: H314, H226, H319H314 on reagent 1 (acetic acid), H226 and H319 on reagent 2 (ethanol)
Precautionary statements: P101, P102, P303+P361+P353, P305+P351+P338, P501
Precautions: Sink, ventilated room, out of reachChild-resistant caps, screwed back on tightly
Storage: 3 years, unopened bottlesExpiry date and batch number printed under the packaging; air wears out an opened bottle

To allow for in addition

Both test tubes: Those from the nitrite testOne receives the treated sample, the other serves as a colour reference: you need two, not one.
Comparator block and colour chart: Those from the nitrite testThe grey block holds the two tubes side by side in front of the colour chart, the only way to read the colour.

8 further specifications are available in the detailed view.

In the box

2 reagent bottles with child-resistant caps, numbered 1 and 2

Manufacturer's values (NO2 test instructions, safety data sheets and 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.

Buy the reagents again, or buy the test again?

Both boxes contain the same chemistry and give the same number of tests. What sets them apart is the accessories, and therefore what you already own.

Two bottles alone do not make a measurement Reading the nitrite requires the grey comparator block, the nine-field colour chart and the two glass test tubes. The refill assumes these three parts are in good condition.

	Reagent bottles (bottles)	Possible tests (tests)	Glass test tubes with screw caps	Sampling syringe	Grey comparator block	Nine-field colour chart	Price
Recommended Reagent refill for NO2 nitrite testYour choice	2 bottles	50 tests	No	No	No	No	$9.00
Nitrite NO2 water test in dropsYour choice	2 bottles	50 tests	Yes	Yes	Yes	Yes	$16.00

Reagent refill for NO2 nitrite testRecommended

What runs out

Reagent bottles (bottles)2 bottles

Possible tests (tests)50 tests

What lasts for years

Glass test tubes with screw capsNo

Sampling syringeNo

Grey comparator blockNo

Nine-field colour chartNo

Budget

Nitrite NO2 water test in drops

What runs out

Reagent bottles (bottles)2 bottles

Possible tests (tests)50 tests

What lasts for years

Glass test tubes with screw capsYes

Sampling syringeYes

Grey comparator blockYes

Nine-field colour chartYes

Budget

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

Documents & manuals

Official manufacturer's instructions, in French

Six-step protocol, order of the two reagents, number of drops, and storage instructions. This is the instruction leaflet for the complete test: it applies equally to the refill, which contains the same reagents.

PDF · 3,1 Mo

Download

Estimate your
delivery time

0.08 kg parcel, dispatched within 48 hours by Colissimo or Chronopost home delivery, your choice at checkout. The two bottles are sent in their original blister pack, which carries the EAN code and the batch number. The exact delivery cost is shown in the 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

How long does a nitrite refill last?

50measurements per refill

32 wksfirst year, cycling monitored day by day

47 wksestablished tank, one measurement a week

The calculation starts from the recommended rhythm: one measurement a day for the first 3 weeks of new freshwater, so 21 measurements, then one a week. A first year run this way uses up the 50 measurements around week 32, a little sooner if you introduce several batches of fish. An established tank, checked once a week with a few extra measurements after an incident, lasts a little under a year.

Is nitrite reagent reordered more often than the other reagents?

Yes, and that is the one real distinguishing feature of this refill. The rate of consumption is quite different from one parameter to the next.

Parameter	Actual rate	Repurchase
Nitrite NO2	Daily at start-up, then weekly without a break	Regular
Ammonium NH4	In bursts: a start-up, then nothing for months	Irregular
Copper Cu	Once after a treatment, sometimes never again	Rare

Nitrite is the only one of the three for which the recommended testing frequency never stops.

Why are there two bottles, and what is each one for?

Because the colour develops in two stages, and the two reagents are added in the same order for every measurement.

Take reagent 1 and add 5 drops to the test tube containing the sample, never to the one used as a reference.
Take reagent 2 and add 5 drops straight afterwards, to the same tube.
Swirl gently after each addition, then leave to stand for 5 minutes.

The two bottles therefore run out at the same rate, and the refill replaces them together.

How many drops are needed per measurement?

Does an aged reagent skew the reading?

A degraded reagent gives a paler colour, and therefore a reading that is too low. The risk is that you feel reassured when nitrite is in fact present.

The check takes a minute: test a sample whose condition you already know, for example just after a large water change on a healthy tank, and compare it with the result you got last time. A colour that is clearly fainter than expected on water that has not changed points to the reagents, not the tank.

What precautions should I take with these two bottles?

Reagent 1 is classed Danger, hazard statement H314: severe skin burns and eye damage. A splash in the eye must be rinsed immediately and at length, with the eyelid held open.

Reagent 2 carries the hazard statements H226 and H319, flammable liquid and eye irritation: the box should be stored away from any flame. Both caps are child-resistant and must be screwed back on fully; a bottle left lying on a shelf ends up seeping along the dropper. Store the box in a dry place, at room temperature, in its original packaging.

After reading, rinse both test tubes with clean water over a sink; the reagents never go into the fish water.

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Reagent refill for NO2 nitrite test

The summary