Fer chélaté EDDHA 6% : poudre rouge sombre présentée en coupelle de laboratoire

Fer chélaté EDDHA 6% : poudre rouge sombre et sa dissolution dans l'eau, coloration rouge orangé

Chelated iron (iron chelate) EDDHA 6%

6,00 €

Weight	Prix	Prix au kg	vs 100 g
100 g	6,00 €	60,00 €	—
500 g	16,50 €	33,00 €	−45 %
1 kg	26,90 €	26,90 €	−55 %
2 kg	48,50 €	24,25 €	−60 %
5 Kg	84,90 €	16,98 €	−72 %

EDDHA iron chelate supplies iron to plants that can no longer absorb it from the water. The EDDHA chelating agent keeps it available up to pH 9, whereas EDTA stops working beyond pH 6.5 – making this the go-to form in hard water or alkaline systems.

Soluble powder, to be diluted in the system water or sprayed onto foliage. It turns the water red for a few days, with no known risk to fish at the recommended dosage.

Weight : 100 g

100 g

500 g

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The summary

What's in the bag: 6% iron chelated by EDDHA, a powder that dissolves up to 120 g per litre of water.
EDDHA, DTPA or EDTA: EDDHA holds up to pH 9, DTPA up to 7.5, EDTA drops off at 6.5.
How to spot a deficiency: young leaves turning yellow with veins remaining green, typically when iron falls below 1.5 mg per litre.
How much to use: 20 to 30 g per 1,000 L, roughly every 3 weeks, to target 2 to 3 mg of iron per litre.
The water turns red — what about the fish: normal colouration lasting a few days, and a usage dose well below the toxicity threshold measured on trout.
Pack sizes: 100 g, 500 g, 1 kg and 2 kg, dispatched from France.

Iron chelate stable up to pH 9, for hard water and alkaline systems

EDDHA iron chelate is a mineral supplement designed for soilless growing systems fed with water whose pH is too high for iron to remain available. Iron itself isn't always lacking: it's present, but precipitated into a form that roots can no longer absorb. The EDDHA chelating agent locks it inside a molecule that keeps it soluble and assimilable, and it's that molecule you're buying, not the iron.

Recognising an iron deficiency before you dose

The sign is clear and shows up on young leaves, never old ones: the leaf blade turns yellow while the veins stay green, giving a distinct net-like appearance. This is iron chlorosis. In aquaponics, it typically appears when dissolved iron drops below 1.5 mg per litre, whereas the target range sits between 2 and 3 mg per litre. The only way to know is to measure, using a colorimetric iron test, before and after application. Our guide to iron deficiency in aquaponics covers the neighbouring symptoms often confused with iron deficiency, particularly manganese and magnesium.

EDDHA, DTPA or EDTA: what actually sets them apart

All three supply iron, but they don't hold up at the same pH, and that's the only criterion that matters when choosing. EDTA releases iron at pH 6.5, DTPA holds up to around 7.5, and EDDHA remains effective up to pH 9 according to chelate suppliers. An aquaponic system often stabilises between 6.8 and 7.4, sometimes higher with hard mains water, that's precisely the zone where EDTA stops being useful. If your pH is drifting upward, our article on pH regulation in aquaponics addresses the cause; EDDHA addresses the consequence. The comparison table puts all three side by side.

EDTA 13 %

The highest iron content and the lowest cost per gram of iron, but only useful below pH 6.5. Suited to soft, acidic water or foliar spraying.

DTPA 11 %

The standard choice for managed hydroponic systems, effective up to around pH 7.5. This is the form that several aquaponic references recommend by default.

EDDHA 6 %

Less iron per kilo and a higher cost per gram of iron, but it's the only one of the three that still works above pH 7.5. It turns the water red.

How much to use, and how often

The standard reference dose in aquaponics is 20 to 30 g per 1,000 litres of system water, renewed roughly every three weeks. Twenty grams suits maintenance in an already balanced system; thirty is for an established deficiency you're trying to correct. Dissolve the powder in a little warm water first, then pour it into the grow bed or sump tank with the pump running. The calculator further down this page works out the right amount for your exact volume, and doses are also listed in the specifications.

Your water will turn red, that's the product doing that

A few minutes after adding it, the water takes on a cherry-red to orange tint that always comes as a surprise the first time. This is neither a reaction, nor a precipitation, nor a problem: it's simply the natural colour of the iron–EDDHA complex in solution, and it fades over a few days as the plants take up the iron. In an ornamental aquarium or a pond where the appearance of the water matters, this is the main argument in favour of DTPA 11 %, which doesn't discolour.

Application can also be done by foliar spraying, directly onto the leaves, which bypasses the pH question entirely since the iron no longer has to go through the roots. This is the fastest route for a plant already showing chlorosis, but it doesn't address the underlying cause and needs repeating. Spray in the early morning or late evening, never in full sun, and wet the underside of the leaves as thoroughly as the top.

What this means for the fish

This is the question that comes up every time you consider adding anything to an aquaponic system, and it deserves a figure rather than a reassurance. Safety data sheets from Fe-EDDHA 6 % manufacturers give a LC50 above 100 mg per litre at 96 hours on rainbow trout, and an EC50 above 100 mg per litre at 48 hours on daphnia. A maintenance dose of 20 g in 1,000 litres represents 20 mg per litre of product. The safety margin exists, but it isn't unlimited: that's reason enough to dose to your actual volume rather than by guesswork, and not to repeat an application without measuring first. The product does not affect pH and does not disturb the biofilter at normal doses.

Storage and handling

Keep the powder in its resealed bag, in a dry place away from heat and in a well-ventilated area. Moisture, which causes clumping, is a greater concern than light. Avoid raising dust when handling it and wash your hands afterwards: the product isn't classified as hazardous, but it's a very stubborn dye on skin, work surfaces, and clothing. A dedicated measuring spoon kept with the bag will save you a good deal of staining.

Iron is just one of the elements an aquaponic system eventually runs short of, and it's rarely the only one. Potassium, calcium, and magnesium also become scarce as the plants grow, without the fish being able to supply them. Our overview of plant deficiencies in aquaponics and our selection of fertilisers suitable for aquaponics put iron in that broader context. If your water stays below pH 6.5, EDTA 13 % will do the same job for less.

Technical specifications

The essentials

Iron content: 6 % chelated FeIron fully chelated by EDDHA, i.e. 60 g of iron per kilogram of product.
Chelating agent: EDDHAEthylenediamine-N,N'-bis(2-hydroxyphenylacetic acid), sodium salt. CAS 16455-61-1.
Stability pH range: 4 to 9Two chelate suppliers give respectively 4 to 10 and up to 9. Several retailers quote 11: this upper limit is not confirmed by any of the manufacturers consulted.
Form: Micro-granulated powderDark red to black, according to the manufacturer's safety data sheet.
Water solubility: 120 g per litre at 20 degreesWell above any practical usage level, so the powder dissolves completely.
Maintenance dose: 20 g per 1,000 LFor an already balanced system, to keep dissolved iron within the target range.
Correction dose: 30 g per 1,000 LFor established chlorosis. Measure before and after rather than dosing blindly.
Application frequency: Approximately every 3 weeksA rough guide for a system in production; adjust based on dissolved iron measurements.

What it does in the water

Target dissolved iron: 2 to 3 mg per litreRange cited in aquaponics. Hydroponic references give 1 to 3 mg per litre depending on the crop.
Symptom threshold: Approximately 1.5 mg per litreBelow this level, ferric chlorosis becomes visible on young leaves.
Water colouration: Cherry red, for a few daysThis is the natural colour of the iron–EDDHA complex. It fades on its own; it is not precipitation.
Effect on pH: No notable effectThis product is not a pH corrector and does not cause pH variation at recommended doses.
Root application: Dilute into system waterPre-dissolve in a small amount of warm water, then pour in with the pump running.
Foliar application: 1 to 2 g per litre of solutionDose sourced from one retailer, not confirmed by a second independent source. Apply out of direct sunlight.

Safety and ecotoxicity

LC50 rainbow trout: Greater than 100 mg per litre96-hour measurement, Fe-EDDHA 6 % safety data sheet. The maintenance dose corresponds to 20 mg per litre.
EC50 daphnia: Greater than 100 mg per litre48-hour measurement on Daphnia magna, same source.
Classification: Not classified as hazardousWithin the meaning of OSHA standard 29 CFR 1910.1200 as cited in the safety data sheet.
Handling precautions: Avoid dustDo not eat or drink during use; wash hands afterwards. Extremely persistent dye.

Packaging and storage

Pack sizes: 100 g, 500 g, 1 kg, 2 kgA 1 kg bag covers approximately 50 maintenance doses per 1,000 litres.
Storage: Dry, cool, ventilatedConditions specified in the manufacturer's safety data sheet.
Container: Reseal after each useMoisture causes the powder to clump, making accurate dosing difficult.
Dispatch origin: FrancePrepared and dispatched from our warehouse.

14 further specifications are available in the detailed view.

In the box

1 resealable bag of EDDHA 6 % iron chelate, in the chosen pack size: 100 g, 500 g, 1 kg or 2 kg
No measuring spoon is included: one should be obtained separately
No iron test is included: the colorimetric iron test is sold separately
No printed instructions are enclosed: dosage and precautions are detailed on this page

Iron content, form, solubility, ecotoxicity, and storage conditions are taken from the safety data sheets of Fe-EDDHA 6 % manufacturers. The stability pH ranges are cross-referenced from two independent chelate suppliers, giving respectively 4 to 10 and up to 9: we use the more conservative range. Doses and frequency are cross-referenced from two French-language aquaponics sources; the foliar dose is based on a single source and is flagged as such.

EDDHA, DTPA or EDTA: which one suits your water

All three supply iron. What separates them is the pH beyond which they can no longer hold it.

	pH range over which iron remains available	Holds above pH 7.5 in hard water	Iron content (%)	Powder required for 2 mg of iron per litre, over 1,000 L	Relative cost per gram of iron	Turns water red	Price per 1 kg bag
Recommended EDDHA 6 %Your choice	4 to 9	yes	6 %	33 g	Highest	yes	26,90 €
DTPA 11 %Your choice	4 to 7	no	11 %	18 g	Mid-range	no	32,90 €
EDTA 13 %Your choice	4 to 6	no	13 %	15 g	Lowest	no	22,90 €

EDDHA 6 %Recommended

Stability by pH

pH range over which iron remains available4 to 9

Holds above pH 7.5 in hard wateryes

Concentration and efficiency

Iron content (%)6 %

Powder required for 2 mg of iron per litre, over 1,000 L33 g

Relative cost per gram of ironHighest

In practice within the system

Turns water redyes

In the shop

DTPA 11 %

Stability by pH

pH range over which iron remains available4 to 7

Holds above pH 7.5 in hard waterno

Concentration and efficiency

Iron content (%)11 %

Powder required for 2 mg of iron per litre, over 1,000 L18 g

Relative cost per gram of ironMid-range

In practice within the system

Turns water redno

In the shop

EDTA 13 %

Stability by pH

pH range over which iron remains available4 to 6

Holds above pH 7.5 in hard waterno

Concentration and efficiency

Iron content (%)13 %

Powder required for 2 mg of iron per litre, over 1,000 L15 g

Relative cost per gram of ironLowest

In practice within the system

Turns water redno

In the shop

The price shown is for the 1 kg bag of each product, in your currency. The pH ranges come from two independent sources: Van Iperen, a iron chelate manufacturer, gives an upper limit of 9 for EDDHA, 7 for DTPA and 6 for EDTA; Custom Hydro Nutrients publishes ranges of 4 to 10, 4 to 7.5 and 4 to 6.5. The table uses the more conservative upper bound from the two, i.e. 9, 7 and 6. The quantities of powder needed to reach 2 mg of iron per litre are calculated from the iron content of each form and then rounded. Above pH 7, EDDHA is the only one of the three that still holds; below that, DTPA and then EDTA work out cheaper per gram of iron delivered.

Estimate your
delivery time

EDDHA iron chelate is a powder not classified as dangerous for transport and is shipped as a standard parcel from France. The stated timeframe covers order preparation, not transit, which depends on the carrier selected at checkout. Exact rates are displayed at checkout in your currency once your address has been entered.

Frequently asked questions

12 questions

6 key questions, 12 in the detailed view

Up to what pH does EDDHA iron remain active?

pH 9the upper limit of EDDHA

pH 7.5beyond this, it's the only one of the three that holds

That's the only reason to prefer it over the other two, and below these values it's oversized: under pH 6.5, EDTA 13% is sufficient and works out the cheapest per gramme of iron; between 6.5 and 7.5, DTPA 11% is the common compromise, including in controlled hydroponics. The comparison table further up shows all three forms side by side, iron content and price included. If you don't know your pH, measure it before buying: it's the only piece of data that changes the answer.

How much EDDHA iron is needed for 1,000 litres?

The standard working reference is 20 to 30 g per 1,000 litres. The procedure to follow:

Measure dissolved iron. Below 1.5 mg per litre, deficiency is established.
Weigh out 20 g for maintenance, 30 g to correct visible chlorosis.
Dissolve the powder in half a litre of lukewarm water, stirring until every grain has disappeared.
Pour into the grow bed or sump tank with the pump running, to distribute the product evenly.
Re-measure after 24 to 48 hours. The target is between 2 and 3 mg per litre.

The dosage calculator on this page works out the figures for your exact volume.

Why does my water turn red after adding it?

Because that is the colour of the dissolved product, not a sign of a problem. The iron-EDDHA complex is cherry red in solution: the tint appears within a few minutes and fades over several days as the iron is taken up by the plants. It is neither a precipitate, nor a reaction with the water, nor an algae bloom.

If water appearance matters — for instance in an ornamental aquarium or a very visible pond — DTPA 11% delivers the same iron without the colouration.

Is EDDHA chelated iron harmful to fish?

At normal working doses, no toxicity has been documented, and there are figures to back that up rather than a simple assertion. Safety data sheets from Fe-EDDHA 6% manufacturers state:

Reference	Concentration	Measure
Rainbow trout	> 100 mg/L	LC50 at 96 hours
Daphnia	> 100 mg/L	EC50 at 48 hours
Maintenance dose	20 mg/L	20 g in 1,000 L, at most one fifth of the threshold

The margin is therefore real but not unlimited, which justifies two simple precautions: dose based on the volume of water actually in circulation, and never repeat an application without measuring dissolved iron in between. At working doses, the product does not affect pH and does not disturb the bacteria in the biofilter.

Does it work in hydroponics, NFT, and planted aquariums?

What quantity is needed for a small 100-litre system?

What happens if I add too much?

A moderate excess mainly results in water that stays red for longer and iron you've paid for unnecessarily.

The risk isn't in a single large dose — it's in repeated additions without any measurement in between. The toxicity threshold measured in fish sits above 100 mg per litre of product, more than five times a maintenance dose: you only reach it by adding blindly. In the event of a genuine overdose, the standard response is a partial water change, as with any excess input.

The water is still red and my leaves are yellowing — is it really an iron deficiency?

The colour tells you iron is in solution; it doesn't tell you iron is the cause. The leaves are what settle the question, and their signature is fairly reliable:

It affects young leaves first, never the older ones.
The blade yellows while the veins remain green, creating a network pattern.
In advanced cases, the leaf turns almost white and then develops necrotic edges.

If the yellowing starts on the old leaves, look towards nitrogen or magnesium instead. Our article on trace element deficiencies in aquaponics helps untangle the confusion.

The water has lost its red tint — is it time to add more?

No. The colour disappears within a few days, whereas on a productive system the next application is typically around three weeks away — the tint would be gone well before then.

The tint is not a timer, and neither is the three-week figure. It's a rough guide, not a schedule: consumption depends on leaf mass, temperature, and light levels. The right approach is to set the frequency based on dissolved iron measurements.

Can it be used as a foliar spray?

Yes. The dose cited by suppliers is 1 to 2 g per litre of spray solution, applied to the foliage. This figure comes from a single source, so we give it as is.

The foliar route bypasses the water pH question entirely, since the iron no longer needs to cross the roots: it is the fastest response for a plant already showing chlorosis. It does not correct the underlying cause and needs to be repeated. Spray in the early morning or late evening, never in direct sun, and make sure to wet the underside of the leaves as well.

Is there a use-by date on the packet?

We do not publish a use-by date: the manufacturers we consulted do not indicate one for this type of chelate in dry powder form.

In its resealed packet, kept dry, cool, and in a ventilated space, the powder retains its activity without notable loss. Its enemy is moisture, far more than light: moisture clumps it into blocks and makes accurate dosing unreliable. It's your scales that suffer first, not the product itself.

Does the product raise or lower the water pH?

How much EDDHA iron for your water volume

Enter the volume of water actually circulating in your system, including grow beds and sump tank. The calculation applies the reference dose of 20 g per 1,000 litres.

System water volume

50 L5000 L

Maintenance dose, to be dissolved then added with the pump running.

Correction dose, for established deficiency

0 g

Reference doses drawn from two French-speaking aquaponics sources: 20 to 30 g per 1,000 litres, roughly every three weeks, to aim for 2 to 3 mg of dissolved iron per litre. These are ballpark figures to be adjusted based on an iron measurement taken before and after each addition, not values to apply without monitoring.

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Chelated iron (iron chelate) EDDHA 6%

The summary

Iron chelate stable up to pH 9, for hard water and alkaline systems

Recognising an iron deficiency before you dose

EDDHA, DTPA or EDTA: what actually sets them apart

How much to use, and how often

What this means for the fish

Technical specifications

EDDHA, DTPA or EDTA: which one suits your water

Estimate your
delivery time

Frequently asked questions

How much EDDHA iron for your water volume

Vous aimerez aussi

Related articles

Iron deficiencies in aquaponics: what should you do?

Recognising deficiencies in aquaponics

Regulating pH in an aquaponic system

Plant deficiencies in aquaponics

Which fertiliser to use in aquaponics?

A practical calendar for success in aquaponics

The 15 plants to grow in aquaponics

Let us talk about your project

Chelated iron (iron chelate) EDDHA 6%

The summary

Iron chelate stable up to pH 9, for hard water and alkaline systems

Recognising an iron deficiency before you dose

EDDHA, DTPA or EDTA: what actually sets them apart

How much to use, and how often

What this means for the fish

Technical specifications

EDDHA, DTPA or EDTA: which one suits your water

Estimate yourdelivery time

Frequently asked questions

How much EDDHA iron for your water volume

Vous aimerez aussi

Related articles

Iron deficiencies in aquaponics: what should you do?

Recognising deficiencies in aquaponics

Regulating pH in an aquaponic system

Plant deficiencies in aquaponics

Which fertiliser to use in aquaponics?

A practical calendar for success in aquaponics

The 15 plants to grow in aquaponics

Let us talk about your project

Estimate your
delivery time