Cardboard box for the NO3 nitrate water test, labelled 40 X TEST

Contents of the NO3 nitrate test: two reagent bottles, two glass test tubes, syringe, double measuring spoon, colour comparator block, and colour chart

Nitrate reading: grey comparator block and two test tubes placed on the colour chart

The two reagents for the NO3 nitrate test, reagent 1 as a powder and reagent 2 as drops

Nitrate NO3 water test, drop format

Name: Nitrate NO3 water test, drop format
Brand: JBL
Price: 2400.0 RSD
Availability: InStock

2,400.00 RSD

800.00 RSD × 3 with no fees Klarna.

This drop-based colorimetric test measures nitrate NO3 in aquariums, ponds, and aquaponic systems, using a colour comparator block and a reference sample. In freshwater, the recommended value should remain below 30 mg/L.

Nitrate is the final stage of the nitrogen cycle: a waste product to dilute in an aquarium, and a nitrogen feed for crops in aquaponics.

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The summary

In the box: 2 reagent bottles, one powder and one drops, 2 glass test tubes, a syringe, a double measuring scoop, a comparator block and a colour chart.
What it measures: dissolved nitrate, on a nine-field colour chart, with a control sample that cancels out the water's own tint.
How long it takes: 12 minutes per measurement, including 10 minutes of waiting, and about 40 measurements per kit.
The useful thresholds: 30 mg/L in a freshwater aquarium, 20 mg/L in seawater, 5 mg/L in a garden pond.
The reading to take once: also measure your top-up water, on its own in a glass. Its level shows whether a water change dilutes the nitrate or adds to it.
Aquatic toxicity: both reagents are harmful to aquatic organisms; no dosed sample ever goes back into the fish's water.

Nitrate drop test, 40 measurements, aquarium, pond and aquaponics

This drop test measures nitrate from 0.5 to 200 mg/L, for about 40 tests, in aquariums, ponds and aquaponics. In aquaponics, the FAO recommends keeping it between 5 and 150 mg/L. Its reagents are toxic to aquatic life: they stay in the test tube, never in the fish's water, and can be bought again as a refill.

Nitrate is the last stage of the nitrogen cycle. Proteins break down into ammonium, ammonium becomes nitrite, nitrite becomes nitrate, and nitrification stops at that stage. In a lightly planted aquarium, the plants absorb too little to offset it, so it accumulates until the next water change.

🔗 The last stage of the cycle

A nitrate level that rises from one week to the next while ammonium and nitrite remain undetectable tells you two things at once. Your biological filter is working, since the bacteria convert everything that reaches them, and your nitrogen consumers are not keeping up with its pace. In a garden pond, this imbalance is mostly found in a heavily stocked koi pond, with no bottom grow medium or planted lagoon zone, or when garden fertilisers run off into the water. The nitrogen cycle unfolds in the same way in an aquarium and in aquaponics, but the conclusion drawn from it differs depending on whether you only raise fish or also grow crops.

High nitrate, ammonium and nitrite at zero

Nitrification is working, but the nitrogen produced is not being consumed enough: add plants or growing surface area, or reduce the fish population.

High nitrate with ammonium

Two separate problems are overlapping. Deal with the ammonium first, as its toxicity is immediate, and correct the nitrate the next day.

Low nitrate in a planted tank

With many plants and only a few small fish, nitrate becomes a deficiency factor and is supplied through a nitrogen fertiliser.

Low nitrate in aquaponics

Pale lower leaves go hand in hand with this figure. The fish load is too low, the biofilter is not yet established, or the plants have taken up everything.

Shake the powder until grey residues appear before reading

Reagent 1 is a powder, and the accuracy of the result depends on shaking. Add the large measuring spoon of reagent 1, then the 6 drops of reagent 2, close the test tube and shake vigorously until only traces of grey powder remain. Then leave it to stand for the full 10 minutes, otherwise the colour will not be fully developed and you will read a value that is too low. Draw both 10 ml samples with the syringe supplied rather than guessing.

🥬 A nitrogen ration for your crops

The same figure can be read in two opposite ways. The aquarist measures nitrate to know when to siphon, because for them it is a waste product to be removed. You, as a grower, measure it to find out whether your lettuces have enough nitrogen to grow: here nitrate is a nitrogen ration that your fish produce and your plants consume. A figure that rises despite well-stocked grow beds is a sign that the balance between the source and the consumers has been lost.

Plan to refill the bottle that was emptied first

Get the reagent refill now, because on a system that is growing crops, nitrate is measured every week and its bottle is the one you will empty first. The glassware, the measuring scoop, the comparator block and the colour chart, for their part, carry over from one purchase to the next. That way you have a whole season of weekly readings in hand without waiting for an order just when the level is rising.

When the level exceeds what your crops take up, several measures can be combined. Regular partial water changes dilute it, a nitrate-reducing filter medium removes some of it, and you can also increase the planted area or reduce the fish stocking. In a garden pond, a sufficient layer of bottom substrate for plants helps. In aquaponics, adding a grow bed is almost always better than draining water loaded with nitrogen that your plants could have taken up. For the balance between fish and crops, see also the article Getting started with an aquaponic system.

🚰 Your top-up water matters

Tap water most often contains nitrate. The French regulatory limit for drinking water is set at 50 mg/L, so perfectly compliant water can still contribute a lot, and the level depends entirely on your municipality. Fill a glass from the tap and test that water on its own: this reading, which you only need to take once, shows whether each water change dilutes the tank's nitrate or adds to it.

🎨 One colour chart, three environments

The colour chart does not carry a single scale, but two rows of figures and three colour bands. The top row is for freshwater and ponds, the bottom row for seawater, because the high salinity weakens the colour of the reaction: the same shade there corresponds to a higher level. Above each field, a pictogram indicates the environment, a fish for the freshwater aquarium, a koi for the pond, a starfish for the reef, and a green, yellow or red band shows whether action is needed. Always read the line for your own environment, because the same value can be green for an aquarium and already yellow for a pond.

These stricter guide values for ponds come down to algae. A high nitrate level only encourages their growth when the water also contains phosphate, and a pond exposed to sun and fluctuating temperatures reacts faster than an aquarium. That is why green water is rarely sorted out without measuring phosphate at the same time as nitrate, on the same sample. The other options, from shading to marginal plants, are covered in the article on green water in ponds.

🫙 Zinc, acids and aquatic life

The powder of reagent 1 contains powdered zinc, tartaric acid and sulfanilic acid; reagent 2 contains a phenylenediamine derivative suspected of causing genetic defects. Both are corrosive, may cause an allergic skin reaction and remain toxic to aquatic life over the long term. This is why the dosed test tube never goes back into the tank: it is emptied down the sink, then rinsed. On an aquaponic system, where nitrate is checked every week to match the fish load to the cultivated area, this routine comes up often; thin gloves and a fixed spot above the sink make it simple. The NO3 reagent refill takes over from the powder bottle.

Technical specifications

Measuring nitrate

Parameter measured: Nitrate, expressed as NO3The last stage of the nitrogen cycle, produced by bacteria from nitrite
Measuring range: 0.5 to 200 mg/LNine-field colour chart, graduated up to 220 mg/L for seawater
Tests per kit: Around 40
Recommended levels: No more than 30 mg/L in freshwater20 mg/L in a marine aquarium, 5 mg/L in a garden pond
Method: Powder, drops and comparator blockThe blank tube cancels out the water's own tint, even in coloured water
Reference: JBL 2412500, PROAQUATEST rangeEAN code 4014162241252

The procedure

Water volume: 2 times 10 mlTwice as much as for ammonium and nitrite. One treated test tube, one control test tube
Reagents to be measured out: 1 level measuring spoon and 6 dropsLarge end of the double measuring scoop for reagent 1, the powder
The steps: Rinse, fill, add reagent, shake, wait, readIn that order. Vigorous shaking is the step most often cut short, and the accuracy of the result depends on it
Waiting time: 10 minutesTime for the colour to develop fully. Reading earlier gives a low value
Total time: About 12 minutesHandling included
Testing frequency: 1 time a weekAlways at the same time, and at least 24 hours after a water change

Hazard labelling

Signal word: DangerOn the powder as on the drops
Pictograms: Corrosion, exclamation mark, health hazard, environmentGHS05 and GHS07 on both bottles, GHS09 on the powder, GHS08 on reagent 2
Hazard statements: H314, H317, H341, H411, H412Burns, skin allergy, suspected genetic defects (reagent 2), long-lasting toxicity to aquatic life
Precautionary statements: P101, P102, P303+P361+P353, P305+P351+P338, P501Label for the doctor, keep away from children, rinse skin and eyes with water, dispose of in accordance with regulations
Precautions: Gloves, sink, out of reachEmpty the treated test tube down the sink and never into the tank: both reagents are toxic to aquatic life
Classified components: Zinc, acids, phenylenediamineZinc powder and sulfanilic acid in reagent 1, m-phenylenediamine dihydrochloride in reagent 2

To allow for in addition

Reagent refills: Reagents only, ref. 2412600The glassware, syringe, measuring scoop, comparator block and colour chart can all be kept
Read with: PhosphateAn algae bloom needs both in the same water: nitrate alone does not explain it

12 further specifications are available in the detailed view.

In the box

2 reagent bottles, one powder and one drops
2 glass test tubes with screw caps
1 graduated sampling syringe
1 double measuring spoon, large and small end
1 grey comparator block, with its reading notch
1 nine-field colour chart and 1 multilingual instruction leaflet, French included

Manufacturer's values (instructions, three-medium colour chart and safety data sheets for both reagents). Aquaponic range taken from the FAO guide.

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.

Nitrate alone, or the whole nitrogen cycle?

The reagents and the comparator block are identical from one offer to the other. What changes is the number of questions the kit answers.

Nitrate on its own, or a test kit? Two questions about your setup, and the table highlights itself.

	Parameters covered	Drop test kits included	Nitrate NO3	Ammonium, nitrite, pH and carbonate hardness	Phosphates, iron, copper, oxygen and silicates	Glass test tubes	Laboratory comparator block	Thermometer	Reagent refill sold separately	Price
Recommended Nitrate (NO3) only testYour choice	1	1	Yes	No	No	2	Yes	No	Yes	2,400.00 RSD
6-in-1 Aquarium Water Testing KitYour choice	6	5	Yes	Yes	No	3	Yes	No	Yes	6,200.00 RSD
JBL ProAquaTest Lab water analysis case, 13 tests for aquarium and pondYour choice	12	13	Yes	Yes	Yes	12	Yes	Yes	Yes	12,000.00 RSD

Nitrate (NO3) only testRecommended

What the kit covers

Parameters covered1

Drop test kits included1

Nitrate NO3Yes

Ammonium, nitrite, pH and carbonate hardnessNo

Phosphates, iron, copper, oxygen and silicatesNo

Equipment supplied

Glass test tubes2

Laboratory comparator blockYes

ThermometerNo

What can be bought separately

Reagent refill sold separatelyYes

6-in-1 Aquarium Water Testing Kit

What the kit covers

Parameters covered6

Drop test kits included5

Nitrate NO3Yes

Ammonium, nitrite, pH and carbonate hardnessYes

Phosphates, iron, copper, oxygen and silicatesNo

Equipment supplied

Glass test tubes3

Laboratory comparator blockYes

ThermometerNo

What can be bought separately

Reagent refill sold separatelyYes

JBL ProAquaTest Lab water analysis case, 13 tests for aquarium and pond

What the kit covers

Parameters covered12

Drop test kits included13

Nitrate NO3Yes

Ammonium, nitrite, pH and carbonate hardnessYes

Phosphates, iron, copper, oxygen and silicatesYes

Equipment supplied

Glass test tubes12

Laboratory comparator blockYes

ThermometerYes

What can be bought separately

Reagent refill sold separatelyYes

Parameters and contents of the two cases taken from their data sheets.

Documents & manuals

Official manufacturer's instructions, in French

Six-step protocol, volumes and dosage of both reagents, recommended thresholds for fresh water, salt water, and ponds, plus explicit mention of nitrate becoming a deficiency factor in a heavily planted tank.

PDF · 1,5 Mo

Download

Estimate your
delivery time

Parcel of 0.15 kg, dispatched within 48 h by Colissimo or Chronopost to your home, as you choose during payment. The reagents are sent in their original box, with the powder and drops kept separate. The exact amount is shown in your basket. Once unsealed, this product can no longer 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

8 questions

6 key questions, 8 in the detailed view

What nitrate level should not be exceeded?

There are three upper limits, one for each environment:

30 mg/Lfreshwater aquarium

20 mg/Lmarine aquarium

5 mg/Lgarden pond

These limits are aimed at aquatic life and algae growth, not at the health of crops.

In aquaponics, the logic is reversed: the FAO guide recommends keeping nitrate between 5 and 150 mg/L and replacing part of the water above that, since your crops feed on it.

My nitrate won't come down despite water changes, why?

Do nitrates really make algae proliferate?

My test shows zero: is that good or a bad sign?

In a pond or a lightly planted tank: this is the result you are aiming for.

In a heavily planted tank or in aquaponics: it is a warning sign. With lots of plants and few small fish, nitrate becomes a deficiency factor, which a nitrogen fertiliser corrects in a planted aquarium. In aquaponics, a persistent zero comes with pale lower leaves, and the cause lies upstream: too few fish being fed, or a biofilter that is not yet converting.

How do you bring nitrates down when water changes are no longer enough?

Test your top-up water. If it is already loaded, no water change will bring the level below its own.
Change water in useful volumes. A third of the volume reduces the gap with the fresh water by a third, no more.
Add nitrogen consumers. Fast-growing plants, growing surface and floating plants are the lever that works continuously.
Reduce the source. Keep fewer fish, or give a more accurate ration. The typical case is a heavily stocked koi pond with no planted area.
Look at phosphate at the same time. If your aim is to limit algae, it matters as much as nitrate.

Why is the first reagent a powder?

Because the reaction first reduces the nitrate, and the reducing agent keeps better dry than dissolved. This is the reason for the double measuring spoon rather than a simple dropper: one large level spoonful of reagent 1, then 6 drops of reagent 2.

A practical consequence, and the first cause of a wrong result: shake the test tube vigorously until only grey powder residues remain. Powder that is not fully dissolved leaves a pale colour, and therefore an underestimated value.

Is the nitrate reagent suspected of being mutagenic?

Both bottles are classified under the signal word Danger: H314, severe skin burns and serious eye damage, and H317, skin allergy. Reagent 2 additionally carries the statement H341, suspected of causing genetic defects.

Three precautions follow: gloves or immediate hand washing, no contact with the eyes, and emptying the treated test tube down the sink and never into the tank, because of the statements H411 and H412, one per reagent, for toxicity to aquatic organisms. Store the box up high: child-resistant caps are no substitute for a closed cupboard.

Can you rely on a reading taken just after a water change?

No, it doesn't describe anything stable: the result is merely an average of the old water and the new. Wait 24 hours for the water to circulate, and always measure at the same point in the week.

Keep two series of readings in the same notebook: the value from the tank and the value from the top-up water. It is the difference between the two, rather than either value alone, that shows whether your system is accumulating nitrogen or receiving it from the mains.

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Nitrate NO3 water test, drop format

The summary