Canna - pH- Organic Acid

An organic pH reducer from CANNA based on 41% citric acid, intended as an alternative to nitric and phosphoric acid. Roughly 2 ml per 10 litres of nutrient solution.

Citric acid gets eaten, and that changes how you work with it

This is the most important difference between this bottle and a mineral pH reducer, and almost no product page mentions it. Phosphoric and nitric acid are inorganic: what you add stays in the reservoir until a root takes it up. Citric acid is an organic compound, which means bacteria can use it as food. As soon as they do, the acid leaves your solution and the pH creeps back up.

How quickly depends on how clean and how cold your reservoir is. A freshly mixed tank at 18 degrees holds for days. A tank that has stood for a week, with a film of slime on the wall, sitting at 24 degrees, can rebound noticeably within a day. CANNA's own instructions accordingly tell you to refresh the reservoir regularly.

That is not a flaw in the product but the price of its advantage. Exactly the same biodegradability is why you can acidify with it without touching soil life and without shifting your NPK ratios. A grower working organically who wants to keep their microbial life intact is buying this property deliberately. A grower running a large recirculating system who would rather not look at the reservoir for a week is better served by a mineral reducer.

You need roughly four times as much of it

CANNA gives around 0.5 ml per 10 litres for the mineral pH- Pro versions. For this Organic Acid the guideline is around 2 ml per 10 litres. That is four times as much, and it is not a fault in the bottle: citric acid is a weak acid, meaning it only partly releases its hydrogen ions in water. You simply need more molecules for the same drop in pH.

Factor that in when comparing. A litre of Organic Acid runs out four times faster than a litre of mineral pH-, so the price per bottle says little about the price per reservoir.

It corrects pH without shifting your schedule

Where phosphoric acid leaves phosphate behind and nitric acid leaves nitrate, citric acid adds neither nitrogen nor phosphorus to your solution. For anyone working to a tight feed schedule that is the second reason to choose this bottle: you correct only the pH, and everything else stays as you calculated it. Citric acid also acts as a chelator, meaning it binds metal ions and keeps them in solution, which helps against scale in lines and drippers.

In use

Mix your nutrients, check the EC, and only then correct the pH. Add in small steps, stir thoroughly and measure again. CANNA gives a recommended value of 5.2 to 6.2 depending on your substrate. Do not mix it directly with pure, undiluted fertilisers. Store the bottle hermetically sealed in its original packaging, between 10 and 30 degrees, out of the sun and out of frost.

Technical Specifications:

• Type: organic pH reducer, liquid concentrate
• Manufacturer: CANNA
• Composition: 41% (m/m) citric acid (C6H8O7)
• Phase: vegetative and generative, no phase split
• Dosage: approximately 2 ml per 10 litres of nutrient solution
• Recommended pH: 5.2 to 6.2 depending on substrate
• Adds: no nitrogen and no phosphorus
• Volume: 1 litre
• Storage: hermetically sealed, in the original packaging, 10 to 30 °C, protected from heat, frost and direct sunlight

Frequently asked questions

Why does my pH creep back up?
Because citric acid is biodegradable and gets broken down by bacteria in the reservoir. The warmer and dirtier the tank, the faster it happens. Refresh the reservoir regularly and measure more often than you would with a mineral acid.

Why do I need so much more of it?
Citric acid is a weak acid and only partly releases its hydrogen ions. Around 2 ml per 10 litres against roughly 0.5 ml for the mineral versions.

Is this suitable for organic growing?
Yes, that is exactly how CANNA positions it: an organic alternative to nitric and phosphoric acid that leaves soil life alone.

Does it change my EC?
Every addition raises EC slightly, and because you dose more of this one the contribution is larger than with a mineral acid. So measure your EC before acidifying, not after.

Can I use it in a drip system?
Yes. Citric acid binds metal ions and actively helps prevent scale in lines and drippers.