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 %

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

Terra Aquatica liquid pH+ pH Corrector is a potassium carbonate corrector that raises the pH of a nutrient solution that has become too acidic, especially with reverse-osmosis or rainwater, which have no buffering capacity. It also supplies silica and potassium. Start at 1 ml per 10 L when the pH drops below 5.5.

This liquid corrector raises the pH of a nutrient solution that has become too acidic. The problem arises mainly with reverse-osmosis water or rainwater: these waters have almost no buffering capacity, so the fertilisers, which are themselves acidic, are enough to make the value drop. Now, below 5.8, calcium is less well absorbed, and below 5.5 most crops fall outside their comfort range.

The active base is a potassium carbonate, guaranteed at 13%, and the analysis declares 10% soluble potassium oxide. The product also supplies silica, at 0.5% silicon dioxide, a sparingly soluble element rarely found in a nutrient solution. Silica strengthens the plant's structure: your stems gain rigidity and the foliage tolerates a temporary lack of water better. The effect on pH is immediate, which means you can measure as soon as the solution is 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

In osmosis water, the pH shifts with every addition because nothing holds it steady. Powdered silicate, rich in silica and alkaline by nature, helps to stabilise it when used from the growth stage onwards at 4 g per 10 litres of solution. You then need to correct with pH+ less often, and the quantities you add with each preparation go down.

🥄 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 doses until it is back between 5.5 and 6.5. In soft water, a few tenths of a millilitre change the value noticeably, and a graduated syringe stops you overshooting the target. Overcorrecting would force you to go back the other way with the pH-minus corrector, which loads your solution with salts without giving the plant anything.

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 case of contact, and never decant the product into a food container. Never mix pH+ and pH-: the reaction is violent and the two cancel each other out. Store the container upright, closed, in a cool, dry place.

🌿 The potassium and silica supplied

Each correction feeds the plant a little. With a density of 1.12, the starting dose of 1 ml per 10 litres weighs 1.12 g and provides around 11 mg of potassium oxide per litre, along with half a milligram of silica. This potassium remains low compared with that of a complete fertiliser, so you do not reduce your fertiliser dose to allow for it. On a system run entirely on osmosis water, where pH+ is used with every preparation, the silica does however build up regularly in the solution. The article on pH regulation explains why water with no buffer 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%, with 10% soluble potassium oxide declared, a 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.

Manufacturer and product safety

Manufacturer: TERRA AQUATICA (SAS, SIREN 840329619), ex General Hydroponics Europe
Postal address: 4 boulevard du Biopole, ZI du Biopole, 32500 Fleurance, France
Contact: info@terraaquatica.com ; +33 5 62 06 08 30
Website: www.terraaquatica.com

Information provided under Regulation (EU) 2023/988 on general product safety.

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?

It depends entirely on your starting water.

Your water	What happens to the pH	What you need
Hard tap water	It rises on its own	Mostly pH-
Reverse osmosis or rainwater	It drops as soon as you add the fertilisers	Mostly pH+
Soft tap water	It swings in both directions	Both, in small amounts

The pH- and pH+ duo brings together both bottles 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

6.5top of the target range

Mix, measure, then add in small doses. The effect is immediate: you can measure as soon as the solution is uniform, without waiting. In reverse osmosis water, a few tenths of a millilitre are often enough, and the quantity that worked the first time will hold for later preparations with the same water.

The concentrate is at pH 12 and carries the H314 warning, severe skin burns and serious eye damage. Wear gloves and goggles, never decant into a food bottle, and if swallowed, rinse the mouth and do not induce vomiting.

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

Your water has no buffering capacity. Whether reverse-osmosis or rainwater, it follows without resistance everything added to it, fertilisers included.
The fertilisers themselves are acidic. The TriPart concentrates are at pH 4.2 for the Grow and 4.47 for the Bloom: pouring them in mechanically lowers the value of the solution.
The roots acidify. By taking up cations, they release protons into the medium, and this increases when the plant is consuming a lot.

That is why the correction is made after adding the fertilisers, never before: correcting first would mean raising the value and then watching it drop again, loading the solution for nothing.

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

It supplies silica, at 0.5% silicon dioxide, which builds up in the cell walls. Your stems gain rigidity, and the plant copes better with a brief spell of water stress. Silica is not among the essential elements, since a plant completes its cycle without it, but it strengthens the structure of crops that receive it regularly.

It also supplies potassium, since the active base is a potassium carbonate. At the quantities used to correct pH, this contribution is marginal compared with the 6% K2O in TriPart Grow: it does not need to be deducted when calculating your nutrient solution.

Does pH+ have a place in an aquaponic system?

pH+ has its place here, but it needs far more caution than in hydroponics. A stocked pond copes poorly with a rapid change in pH, and nitrification slows down when the pH shifts abruptly.

This is also the most common direction of correction in aquaponics: an established system acidifies naturally as a result of nitrification, so you are more often looking to raise the pH. In a stocked pond, this correction is made slowly, in small amounts diluted beforehand in a bucket of system water and spread over several days, with a daily pH check. The article on pH regulation in aquaponics details the precautions specific to ponds.

What size pH+ bottle should I get?

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Liquid pH corrector pH+

The summary