Bottle of liquid pH+ corrector on a white background

Nutrient availability chart by pH, showing the overly acidic zone that pH+ corrects

Liquid pH corrector pH+

9,90 €

Capacity	Price	Price per L	vs 500 ml
500 ml	9,90 €	19,80 €	—
1 L	13,90 €	13,90 €	−30 %
5 L	59,90 €	11,98 €	−39 %
10 L	99,90 €	9,99 €	−50 %

3,30 € × 3 with no fees Klarna.

This liquid pH corrector based on potassium carbonate raises and stabilises the pH of an overly acidic nutrient solution, whether on RO water, rainwater or an inert grow medium, while also supplying potassium and silica. It is suitable for use in hydroponics, coco fibre and soil, and is available from 500 ml to 10 L. This concentrate is classified as corrosive H314.

Ref. TA-PHP-500·pH adjuster

Capacity : 500 ml

500 ml

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The summary

What it is: a potassium carbonate-based alkaline pH adjuster, used to raise the pH of a solution that has become too acidic.
What else it provides: silica, which strengthens plant structure, and a small amount of potassium.
Which water it suits: primarily reverse osmosis water and rainwater — both unbuffered — whose pH drops sharply as soon as fertiliser is added.
How much to use: 1 ml per 10 L as a starting dose when pH is below 5.5, then adjust in small increments.
Caution: concentrated corrosive solution, H314, pH 12. Gloves and eye protection must be worn, as with pH-.
Sizes and dispatch: 500 ml, 1 L, 5 L or 10 L, dispatched from France.

Raises pH and adds silica, for soft and RO water

This liquid corrector raises the pH of a nutrient solution that has become too acidic. This most commonly occurs with reverse osmosis water or rainwater: these have virtually no buffering capacity, meaning that fertilisers, which are themselves acidic, are enough to cause the value to drop sharply. Below 5.8, calcium uptake is reduced, and below 5.5 most crops fall outside their comfortable growing range.

The active base is potassium carbonate, guaranteed at 13%, equating to 10% soluble potassium oxide. The product also supplies silica at 0.5% silicon dioxide, a poorly soluble element rarely found in a nutrient solution. Silica strengthens the plant's structure: your stems gain in rigidity and the foliage tolerates temporary water stress more effectively. The effect on pH is immediate, allowing you to take a reading as soon as the solution has been mixed.

🌊 Water with no buffering capacity

Osmosis or rainwater

This is its main use, as with very soft water or a solution that has come out of an overcorrection with pH-.

Hard water from the mains

Its bicarbonates raise the pH again after each correction: it is pH- that is needed in this case, rarely pH+.

After an overcorrection

Dilute first with uncorrected water, then measure before adding pH+.

Stabilise RO water with silicate

With reverse osmosis water, the pH shifts with every addition because there is nothing to buffer it. Silicate powder, which is rich in silica and carbonates, helps to stabilise it when used from the growth stage at 4 g per 10 litres of solution. You will then need to adjust with pH+ less frequently, and the amount added at each preparation will decrease.

🥄 Dosing in small increments

Measure the pH after adding the fertilisers. If it is below 5.5, start with 1 ml per 10 litres of solution, mix, measure again, then repeat in small increments until you are back between 5.5 and 6.5. With soft water, a few tenths of a millilitre can shift the value noticeably, and a graduated syringe helps you avoid overshooting. Overcorrecting would mean having to bring the pH back down with a pH- corrector, which adds salts to your solution without benefiting the plant.

An alkali burns just like an acid

The concentrate is at pH 12 and classified H314: it causes severe skin burns and serious eye damage. Wear gloves and goggles, rinse thoroughly in the event of contact, and never decant the product into a food container. Never mix pH+ and pH- together: the reaction is vigorous and the two cancel each other out. Store the bottle upright, sealed, in a dry and cool place.

🌿 The potassium and silica supplied

Each correction also feeds the plant slightly. At a density of 1.12, the starting dose of 1 ml per 10 litres weighs 1.12 g and delivers approximately 11 mg of potassium oxide per litre, along with half a milligram of silica. This potassium level is modest compared with that of a complete fertiliser, so there is no need to reduce your fertiliser dose to account for it. In a system run entirely on reverse osmosis water, where pH+ is used at every preparation, silica does however build up steadily in the solution. Our article on pH regulation explains why water with no buffering capacity is harder to keep stable than hard water.

Technical specifications

The essentials

Function: Raises pHImmediate effect. An alkaline adjuster, the pH+ counterpart in the range.
Active base: Potassium carbonateGuaranteed at 13%, equating to 10% soluble potassium oxide, a key nutrient.
Additional input: Silica, 0.5% SiO2Silica strengthens plant structure and stem rigidity.
pH of concentrate: 12Highly alkaline concentrate, as corrosive as an acid.

Use

Appearance: Pale blue liquidThe pH- from the same range is yellowish: the two bottles cannot be confused.
Waters concerned: RO water, rainwater, very softWith hard tap water, pH- is the product you'll reach for most often.
First addition: 1 ml per 10 LIf the pH is below 5.5. Then add small doses at a time until it reaches 5.5 to 6.5.
Relative density: 1.12One litre weighs approximately 1.12 kg.

Safety and storage

Classification: Danger, H314Causes severe skin burns and serious eye damage. Corrosive, category 1A.
Essential equipment: Gloves and gogglesPrecautionary statements P264 and P280. Wash your hands thoroughly after handling.
Incompatibility: Never mix with pH-The alkaline concentrate and the acid concentrate react vigorously and cancel each other out: each one is added to water, never to the other.
Storage: Upright, sealed, dry and coolIn its original packaging, away from acids and foodstuffs. Shelf life of 5 years after opening.

To budget for separately

pH measurement: Drop test kit or pH meterIn soft water, a few tenths of a millilitre will shift the reading: check it after every addition.
Graduated syringe: Readable to the nearest tenth of a millilitreWith reverse-osmosis water, doses are measured in tenths of a millilitre.

6 further specifications are available in the detailed view.

In the box

1 bottle of liquid pH+ corrector in the chosen size: 500 ml, 1 L, 5 L or 10 L.

H314 classification, potassium carbonate, pH, density, and appearance: French safety data sheet dated 08/01/2024. Guaranteed analysis, starting dose, and storage: official French product sheet checked on 07/10/2026.

pH- or pH+: which one your water needs

Both correct the pH, but in opposite directions. The choice depends on your source water.

Raising pH is rarely needed with tap water pH+ is aimed at unbuffered water where the pH drops as soon as a fertiliser is added. Three signs indicate this before the first measurement is taken.

	Effect on the solution	Water concerned	Active base	pH of concentrate	Liquid colour	Supplies phosphorus	Provides potassium	Silica source	Classified corrosive H314	Gloves and goggles must be worn	Never to be mixed with the other
pH- correctorYour choice	Lowers pH	Hard tap water	Nitric, phosphoric, citric acids	1	Yellowish	Yes	No	No	Yes	Yes	Yes
Recommended pH+ correctorYour choice	Raises pH	Reverse osmosis or rainwater	Potassium carbonate	12	Pale blue	No	Yes	Yes	Yes	Yes	Yes

pH- corrector

What each one does

Effect on the solutionLowers pH

Water concernedHard tap water

Active baseNitric, phosphoric, citric acids

pH of concentrate1

Liquid colourYellowish

What it adds on top

Supplies phosphorusYes

Provides potassiumNo

Silica sourceNo

Safety

Classified corrosive H314Yes

Gloves and goggles must be wornYes

Never to be mixed with the otherYes

pH+ correctorRecommended

What each one does

Effect on the solutionRaises pH

Water concernedReverse osmosis or rainwater

Active basePotassium carbonate

pH of concentrate12

Liquid colourPale blue

What it adds on top

Supplies phosphorusNo

Provides potassiumYes

Silica sourceYes

Safety

Classified corrosive H314Yes

Gloves and goggles must be wornYes

Never to be mixed with the otherYes

Compositions, pH values of the concentrates and classifications: French safety data sheets, version dated 22 November 2023 for pH- and 8 January 2024 for pH+. Descriptions taken from the 2025 French catalogue. Values recorded on 10 September 2026.

Documents & manuals

Safety data sheet for pH+, in French

Version dated 8 January 2024. H314 classification, potassium carbonate content, protective equipment required, and what to do in the event of contact or ingestion.

PDF · 4

Download

Safety data sheet for pH+, in English

Safety data sheet, version 8, dated 8 January 2024. Same content as the French version: H314 classification, potassium carbonate content, protection and action to take. Document in English.

PDF · 4

Download

TriPart application chart, with pH targets by growth stage, multilingual document

The pH and conductivity ranges to aim for at each stage of growth. A multilingual document in which French and English appear side by side.

PDF · 4

Download

Estimate your
delivery time

A corrosive product under CLP classification, dispatched in its original packaging by tracked parcel from France. Weight ranges from approximately 550 grams for the 500 ml to approximately 5.5 kg for the 5 L. Exact shipping costs and 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.

Frequently asked questions

6 questions

6 key questions

Do I really need the pH+ or is the pH- enough on its own?

This depends entirely on your source water.

Your water	What happens to the pH	What you need
Hard tap water	It rises on its own	Mostly pH-
RO or rainwater	It drops as soon as fertiliser is added	Mostly pH+
Soft tap water	It shifts in both directions	Both, in small amounts

The pH- and pH+ duo brings both bottles together for this third case.

How much pH+ is needed for 10 litres of water, and what precautions should be taken?

1 mlto start with, per 10 L

5.5threshold below which to correct

6.5upper end of the target range

Mix, measure, then add in small increments. The effect is immediate: you can measure as soon as the solution is homogeneous, with no need to wait. With osmotic water, a few tenths of a millilitre are often enough, and the quantity that worked the first time will hold for subsequent preparations using the same water.

The concentrate is at pH 12 and is labelled H314, causes severe skin burns and serious eye damage. Wear gloves and goggles, never decant it into a food container, and in the event of ingestion, rinse your mouth without inducing vomiting.

Why is my pH dropping when I am not adding any acid?

Your water has no buffering capacity whatsoever. Whether it is reverse-osmosis or rainwater, it follows without resistance everything added to it, fertiliser included.
The fertilisers themselves are acidic. The TriPart concentrates sit at pH 4.2 for Grow and 4.47 for Bloom: adding them mechanically lowers the pH of the solution.
Roots acidify the solution. By taking up cations, they release protons into the medium, and this effect intensifies when the plant is growing vigorously.

This is precisely why correction must be made after adding the fertilisers, never before: correcting first would simply mean raising the value only to watch it drop again, loading the solution with corrector for no benefit.

What does it provide for the plant, beyond raising the pH?

It supplies silica, at 0.5% silicon dioxide, which accumulates in cell walls. Your stems become more rigid, and the plant tolerates short periods of water stress more readily. Silica is not classed as an essential element — a plant can complete its life cycle without it — but it strengthens the structure of crops that receive it regularly.

It also supplies potassium, since the active base is potassium carbonate. At the quantities used for pH correction, this input remains negligible compared with the 6% K2O in TriPart Grow: it does not need to be deducted from your nutrient solution calculation.

Does pH+ have a place in an aquaponic system?

pH+ has its place here, but requires far more care than in hydroponics. A stocked pond does not tolerate rapid pH swings well, and nitrification slows whenever pH changes abruptly.

This is, in fact, the most common direction of correction in aquaponics: an established system naturally acidifies under the effect of nitrification, so the usual aim is to raise the pH. In a stocked pond, this correction should be made gradually, in small amounts spread over several days, with a daily pH check. Our article on pH regulation in aquaponics sets out the specific precautions for pond systems.

What size pH+ bottle should I get?

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Liquid pH corrector pH+

The summary