Tub of Terra Aquatica pH- powder pH corrector, 250 g format, on a white background

Tub of Terra Aquatica pH- powder pH corrector, 500 g format, on a white background

Pot of Terra Aquatica pH- powder pH corrector, 1 kg format, on a white background

Bucket of Terra Aquatica pH- powder pH corrector, 5 Kg format, on a white background

pH- down corrector in powder form for nutrient solution

$6.00

Capacity	Price	Price per kg	vs 25 g
25 g	$6.00	$240.00	—
250 g	$18.00	$72.00	−70 %
500 g	$23.00	$46.00	−81 %
1 kg	$32.00	$32.00	−87 %
5 kg	$86.00	$17.20	−93 %

$2.00 × 3 with no fees Klarna.

This pH- powder lowers the pH of a nutrient solution or irrigation water. It is made from pure urea phosphate, a crystalline salt that keeps for 5 years after opening, can be transported without any risk of leaks, and can be weighed to the gram.

Ref. TA-PHDRY-25·pH corrector

Capacity : 25 g

250 g

500 g

Customer support 7 days a week by email

Delivery within 2 to 15 business days

100 % secure payment

The summary

What it is: pure urea phosphate in powder form, for lowering the pH of a nutrient solution.
Dosage: 1 g dissolved in 5 to 6 litres of water gives a correction solution, which you add in small amounts while monitoring the pH.
What it also provides: phosphorus and nitrogen, since urea phosphate is made from urea and phosphoric acid.
Corrosive product: Danger classification, corrosion pictogram, H314 statement. Gloves and eye protection are required, and the powder must always be dissolved before being added.
Five formats: 25 g, 250 g, 500 g, 1 kg, and 5 kg. The price per kilo drops noticeably with larger quantities.
Dispatch: tracked parcel from France, from a lightweight sachet to a 5 kg bucket.

pH corrector in powder form, pure urea phosphate, available from 25 g to 5 kg

In soilless growing, pH controls the uptake of nutrients. An element present in your solution but made unavailable by a pH that is too high will not be absorbed by the plant, so you observe the symptoms of a deficiency even though the fertiliser was dosed correctly. This powder corrector lowers the value of the solution, and it should always be dissolved before being added.

🧂 Pure urea phosphate

The powder is pure urea phosphate, CAS number 4861-19-2, at 100%. This crystalline salt becomes strongly acidic once dissolved, with a pH of 2.7 to 2.8 in solution. Its solubility reaches 100 g per litre at 20 °C, meaning that one gram dissolves completely in the 5 to 6 litres of a correction solution. The powder form has a clear practical advantage: nothing leaks in transit, and the product keeps for 5 years after opening.

Adjusting the pH

Dissolve 1 g in 5 to 6 L of water, then add this solution to the reservoir in small amounts.

Cleaning a system

Circulate 1 g per litre of water overnight, then rinse with clean water: the acidity dissolves salt deposits.

Cleaning the foliage

Spray 1 g dissolved in 10 L to remove product residues deposited on the leaves.

Storage

Keep the powder dry in a sealed container. It is hygroscopic and clumps into lumps if it absorbs moisture.

🧰 The powder and the liquid

A powder does not freeze and carries no risk of leakage in transit, which makes it the ideal form for large volumes and stocks kept over several seasons. Liquid pH-, on the other hand, can be dosed more precisely in small reservoirs, where weighing half a gram requires an accurate set of scales. The choice therefore comes down to the volume you are treating at one time rather than the price per kilogram.

Measure the pH before and after each adjustment

The drop pH test kit gives you the value of your solution in one minute, before correction and after each addition. As the correction solution has a strong effect on poorly buffered water, this reading prevents the pH from dropping below 5.5. You dose the powder based on a measurement, rather than by guesswork.

Dissolve the powder before adding it to the reservoir

Never add the dry powder directly to a grow bed or reservoir. Dissolve it first in a small amount of water, pour it into an area where the water is circulating, allow it to homogenise, then take your reading. The product is classified as skin corrosion category 1B under hazard statement H314, so wear gloves and goggles, avoid breathing the dust, and keep the container out of reach of children.

📉 Correct without overdoing it

pH correction is always made in small increments, never all at once, because the curve is not linear and a slight excess can cause the value of a low-buffered water to drop sharply. Prepare a diluted stock solution, add a fraction of it, stir, wait a few minutes, and re-measure before adding more. Always correct last, after the fertilisers have been added, since each one affects the value. Finally, note down the quantity that worked for your usual volume, and subsequent corrections will take no more than a minute. Our article on pH regulation explains this method in detail.

🧪 What the correction adds

Correcting pH with urea phosphate also affects nutrition. The powder contains 17% nitrogen and 44% phosphoric anhydride: each gram added to a 50-litre reservoir therefore introduces 3.4 mg of nitrogen and nearly 9 mg of phosphoric anhydride per litre. These amounts remain small with a minor correction, but they add up with very hard water that requires several grams at each preparation. During flowering, when nitrogen requirements decrease, this input is added on top of the nitrogen from the fertiliser. With hard water and towards the end of the cycle, this nitrogen must therefore be factored into the fertiliser dosage, which is reason enough to know the hardness of your water before choosing your pH corrector.

Technical specifications

Composition

Composition: Urea phosphate, 100%CAS number 4861-19-2.
Shape: Crystalline powderAcidic once dissolved. It won't leak, won't freeze, and keeps for 5 years after opening.
Secondary inputs: Nitrogen 17%, P2O5 44%Urea phosphate is made from urea and phosphoric acid: it enriches the solution while also acidifying it.
Storage: In a cool, dry place, sealedThe powder is hygroscopic. A poorly sealed pot will produce lumps that are impossible to weigh accurately.

Dosage and use

Correction solution: 1 g per 5 to 6 LConcentration of the correction solution, to be added in small amounts. Measure after each addition.
System cleaning: 1 g per litreOne night of circulation dissolves salt deposits, followed by a thorough rinse with clean water.
Foliage cleaning: 1 g per 10 LSprayed on, this dilution removes product residues from leaves.
Method: Dissolve then pourNever add the dry powder directly to the reservoir. Dissolve it in a little water, pour into an agitated area, allow to homogenise, then measure.

Safety and conditions of use

Ranking: Corrosive, category 1BDANGER label, corrosion pictogram. H314 statement: causes severe skin burns and serious eye damage.
Precautions: Gloves and gogglesSafety advice P280, P260 do not breathe dust, P102 keep out of reach of children.
Target working range: pH 5.5 to 6.5Target range in hydroponics, on coco coir or in soil. In aquaponics, the target is higher.
Use in aquaponics: Not recommended in a stocked pondThe urea added turns to ammonia in a stocked pond, and the phosphorus feeds algae growth.

To budget for separately

Gram-accurate scales: Accurate to the gramDoses are weighed out: 1 g per 5 to 6 litres of correction solution.
pH measurement: Drop test kit or pH meterThe right dose depends on your water, and only a test will tell you.

6 further specifications are available in the detailed view.

In the box

1 sachet of 25 g, or 1 tub of 250 g, 500 g or 1 kg, or 1 bucket of 5 kg of pH- powder corrector, depending on the size chosen

Doses, pH range, rinsing method, guaranteed analysis and storage taken from the official French data sheet on 07/10/2026; composition, CAS number, classification and safety recommendations: safety data sheet V6 dated 10/01/2024.

Powder or liquid: what really sets the two pH correctors apart

Both lower pH. They differ in composition, storage requirements, and the secondary effects each has on the solution.

Both lower the pH, but not in the same hands The powder is weighed and dissolved in advance; the liquid is measured drop by drop. The powder is a urea phosphate, and that urea rules it out for a stocked pond.

	Active base	Supplies urea	Supplies phosphorus	Declared urea nitrogen (%)	Organic buffer, citric acid	Resting state	Prior dissolution	Drop-by-drop dosing	Storage after opening	Classified corrosive H314	Gloves and goggles must be worn	Risk of inhaled dust	Risk of splashing
Recommended pH- powderYour choice	Pure urea phosphate	Yes	Yes	17 %	No	Inert powder	Yes	No	5 years	Yes	Yes	Yes	No
pH- liquidYour choice	Nitric, phosphoric, citric acids	No	Yes	0 %	Yes	Liquid acid	No	Yes	5 years	Yes	Yes	No	Yes

pH- powderRecommended

What's inside

Active basePure urea phosphate

Supplies ureaYes

Supplies phosphorusYes

Declared urea nitrogen (%)17 %

Organic buffer, citric acidNo

Day to day

Resting stateInert powder

Prior dissolutionYes

Drop-by-drop dosingNo

Storage after opening5 years

Safety

Classified corrosive H314Yes

Gloves and goggles must be wornYes

Risk of inhaled dustYes

Risk of splashingNo

pH- liquid

What's inside

Active baseNitric, phosphoric, citric acids

Supplies ureaNo

Supplies phosphorusYes

Declared urea nitrogen (%)0 %

Organic buffer, citric acidYes

Day to day

Resting stateLiquid acid

Prior dissolutionNo

Drop-by-drop dosingYes

Storage after opening5 years

Safety

Classified corrosive H314Yes

Gloves and goggles must be wornYes

Risk of inhaled dustNo

Risk of splashingYes

Compositions and classifications: French safety data sheets, V6 dated 10/01/2024 for the powder and V8 dated 22/11/2023 for the liquid. Guaranteed analyses and storage: official French data sheets retrieved on 07/10/2026.

Documents & manuals

Safety data sheet, pH- Powder

Manufacturer's regulatory document, in English. It gives the exact composition, the CAS number, and the hazard statements.

PDF

Download

Manufacturer's page, pH management

Overview of liquid and powder pH adjusters, with indicative dosages, in English.

LIEN

Download

Estimate your
delivery time

A non-fragile product, dispatched as a tracked parcel from France. The 5 kg format is a heavy but compact package. Exact shipping costs and final delivery times are shown at checkout once your address has been entered. Outside the European Union, import duties and taxes remain the responsibility of the recipient. Delivery times run from the date of dispatch, excluding public holidays.

Frequently asked questions

6 questions

6 key questions

What quantity is needed to lower the pH?

1 gin 5 to 6 L, correction solution

5.5lower end of target range

6.5upper end of target range

This solution is then added to the reservoir in small amounts, and the quantity required depends on the hardness of your water. Rainwater needs only a few millilitres to correct, whereas hard water requires considerably more, and its pH will then drop sharply once its bicarbonates are neutralised. Add in small doses, stir, measure, and repeat.

Powder or liquid — which should you choose?

Point	Powder	Liquid
Storage	5 years after opening, keep dry	5 years after opening, frost-free
Transport	no leakage risk	risk of leakage
Precise dosing	scales required	by the drop
Small volumes	tricky	easier
Secondary inputs	phosphorus and nitrogen	small amounts of phosphorus and nitrogen

For large volumes and long-term stock, powder wins out. For a small tank corrected drop by drop, the liquid is more convenient. One final practical note: powder is hygroscopic, and a poorly sealed container produces lumps that remain effective but can no longer be weighed accurately.

Does this product affect nutrition?

Yes. This is 100% pure urea phosphate, CAS number 4861-19-2: urea and phosphoric acid. Each correction therefore adds phosphorus and nitrogen to your solution.

For small adjustments, the effect is negligible. On hard water that requires repeated doses with each water change, it becomes significant — particularly during flowering, when nitrogen requirements decrease. If your water is very hard, consider treating it upstream rather than allowing inputs to accumulate.

Is urea phosphate suitable for a pond with fish?

Keep it away from fish. The urea it contains is converted into ammonia by bacteria, which is toxic to fish, and the phosphorus encourages algae growth. In a stocked pond, pH correction should be carried out with other products and different targets.

Our article on pH regulation in aquaponics covers this specific case, and the liquid pH- can be dosed more precisely in smaller volumes.

How do you add it to a tank, and what precautions should you take?

This is a corrosive product: DANGER labelling, corrosion pictogram, H314 statement, causes severe skin burns and serious eye damage. Wear gloves and eye protection, do not breathe the dust, and keep it out of reach of children.

Weigh the dose using scales accurate to the gram.
Dissolve it in 5 to 6 litres of water per gram, in a separate container.
Add this solution to the reservoir in fractions, in a well-circulated area, with the pump running.
Allow a few minutes for the solution to homogenise, then take a reading.
Repeat if necessary, in small increments — a pH that has dropped too low takes longer to correct than one that is still slightly high.

The same product can be used to descale a blocked irrigation circuit at 1 gram per litre: the acidity dissolves the white salt deposits that clog the nozzles. Allow the solution to circulate overnight. Rinse thoroughly with clean water before starting a crop again.

Which size to choose?

The 25 g size is ideal for a first trial, or as a top-up quantity to keep beside a small system.
The 250 g size suits one or two home systems.
The 500 g size is the standard format for a season across several pots.
The 1 kg size works for multiple systems, or for hard water that requires repeated doses.
The 5 kg size is suited to production use, or for regular circuit cleaning. The price per kilogram is the lowest at this size.

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pH- down corrector in powder form for nutrient solution

The summary