Soft water corrector with calcium and magnesium
Regular price
$15.00
Regular price
Sale price
$15.00
Unit price
/
per
| Contenance | Price | Price per L | vs 1 L |
|---|---|---|---|
| 1 L | $15.00 | $15.00 | — |
| 5 L | $52.00 | $10.40 | −31 % |
| 10 L | $103.00 | $10.30 | −31 % |
CANNA's CALMAG AGENT is a concentrate of calcium and magnesium, in a ratio of 3 to 1, which corrects water that is too soft or comes from reverse osmosis before the fertiliser is added. A few tenths of a millilitre per litre are enough to raise the water's conductivity to 0.4 mS/cm, the baseline for which the brand's fertilisers are formulated.
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The summary
- What it contains: a liquid concentrate of calcium and magnesium, in a ratio of 3 to 1.
- Gradually: 0.1 to 0.5 ml per litre, until the water reaches 0.4 mS/cm.
- Suitable water: soft, rain or reverse osmosis water, below 0.4 mS/cm.
- What you need: a conductivity meter to measure the water before and after each addition.
- Pond side: not in the fish water, where calcium is supplied by bases and carbonates.
- Yield per litre: it corrects 2,000 to 10,000 litres of water depending on how soft it is.
The calcium and magnesium that soft water, whether rainwater or from a reverse osmosis unit, lacks
CANNA CALMAG AGENT is a calcium and magnesium concentrate, in a ratio of 3 to 1, which corrects soft, rain or reverse-osmosis water. It is added gradually, from 0.1 to 0.5 ml per litre, until the water reaches 0.4 mS/cm, after which the CANNA fertiliser takes over. The water of an aquaponic system, however, never receives it.
Very soft water, rainwater or water that has passed through a reverse osmosis unit seems perfect for watering, since it is almost pure. That is precisely its flaw: it lacks the calcium and magnesium that ordinary tap water provides, and fertilisers, which count on that supply, then leave the plant with a deficiency. CALMAG AGENT restores these two elements to the water before you add the fertiliser, so that you start again from the base for which the nutrient solution was calculated.
The two elements do not play the same role. Calcium is involved in building cell walls, and a shortage shows first in the fast-growing parts of the plant: scorched tips on young lettuce leaves, necrosis at the end of tomatoes. Magnesium sits at the heart of the chlorophyll molecule, so a deficiency yellows the leaf blade between the veins of the older leaves. The 3 to 1 ratio of the concentrate respects the balance sought between these two elements, which compete at the roots when one dominates the other too much.
💧 Read your water first
Everything starts with the conductivity of the water, measured with a conductivity meter and expressed in mS/cm. CANNA fertilisers for soil and for coco fibre, such as Terra Vega or Coco A+B, are formulated for so-called normal water, from 0.4 to 0.5. Below 0.4, your water is soft and CALMAG AGENT tops it up. Between 0.4 and 0.5, it naturally contains enough calcium, magnesium and bicarbonates, and no addition is needed. Above 0.5, it is hard or loaded with sodium and chlorides: you either dilute it with reverse osmosis water down to 0.4, or start from pure reverse osmosis water that you build back up with CALMAG AGENT.
Freshwater
Below 0.4 mS/cm, add CALMAG AGENT until you reach 0.4.
Normal water
From 0.4 to 0.5 mS/cm, nothing needs to be added before the fertiliser.
Hard water
Above 0.5, the water is cut with osmosis water, then topped up if needed.
Measuring tap water with a pocket tester
The whole dosing process relies on a conductivity reading, and an accurate tester saves you from correcting water that does not need it. The ARKA myAqua pH, EC and TDS tester measures conductivity and pH in one go, which also helps you adjust the solution once the fertiliser has been added. A first reading from the tap tells you straight away whether CALMAG AGENT is relevant to you, and the quantity you work out the first time stays valid for as long as your source water does not change.
Do not add anything to water that is already hard
In hard water, above 0.5 mS/cm, adding calcium and magnesium unbalances the solution and loads the grow medium with salts. So measure before adding anything. Keep the bottle closed, in its original packaging, between 10 and 30 °C, away from sunlight and frost.
Dosing is done step by step. Shake the bottle, fill the sump tank with water at 20 to 22 °C, then add CALMAG AGENT in small amounts, 0.1 to 0.5 ml per litre, measuring the conductivity until it reaches 0.4 mS/cm. For a 50 litre sump tank, that means 5 to 25 ml depending on the starting water, and for a 10 litre watering can, 1 to 5 ml. Only then do you add your usual fertiliser and additives, and then adjust the pH. The product can be used on all grow media: soil, coir, rockwool or clay pebbles.
Poor quality water, very high in sodium or chlorides, calls for one more step. Mix it with reverse osmosis water down to a conductivity of just 0.2 mS/cm, then top up with CALMAG AGENT to 0.4. The proportion of unwanted salts falls markedly, while the useful calcium and magnesium return to their level. This method also suits rainwater collected from a roof, whose conductivity varies from one shower to the next and which is best measured each time you refill.
🐟 Calcium in an aquaponic circuit
An aquaponic system filled with rainwater or reverse osmosis water also lacks calcium and magnesium, as well as buffering capacity, measured by carbonate hardness (KH), which the FAO manual recommends keeping between 60 and 140 mg/L. CALMAG AGENT was designed to prepare irrigation water and nutrient solutions, not the fish water, so you should not pour it into the pond. The system's calcium is better supplied by calcium-based bases, such as calcium hydroxide alternated with potassium hydroxide when the pH drops below 6.4, or by calcium carbonate, of which the FAO recommends 2 to 3 handfuls per 1,000 litres in a porous bag, removed as soon as the pH exceeds 7.
These calcium inputs benefit leafy vegetables, in which they limit leaf tip burn, while raising KH and pH. A carbonate hardness test tells you when to step in. CALMAG AGENT, however, keeps its full place around the system: for separate hydroponics, for seedlings and for pots watered with rainwater, and for the plant loop of a decoupled aquaponic system, whose water does not return to the fish. The article on rainwater in aquaponics details the precautions specific to the fish circuit.
📦 Sizes and storage
At 0.1 to 0.5 ml per litre, a 1 litre bottle treats 2,000 to 10,000 litres of water, depending on how soft your starting water is. The 5 litre container is intended for a greenhouse watered with rain water all year round, and the 10 litre one for large sump tanks and professional installations. Keep the bottle tightly closed in its original packaging, between 10 and 30 °C, away from heat, frost and direct sunlight.
Technical specifications
The product
- Type
- Liquid calcium and magnesium concentrate
- Ratio
- Calcium 3 to magnesium 1
- For which water
- Soft or reverse osmosis water, below 0.4 mS/cm
- Grow media
- All
Usage
- Dose
- 0.1 to 0.5 ml per litreAdd gradually while measuring
- Aim
- Water at 0.4 mS/cm before fertiliser
- Water for preparation
- 20 to 22 °C
- Storage
- 10 to 30 °C, away from frost and sunlight
- Poor-quality water
- Dilute to 0.2 mS/cm, then top upA mix of osmosis water and tap water
- Aquaponic circuit
- Away from the fish waterSeparate hydroponics, seedlings, decoupled loop
2 further specifications are available in the detailed view.
In the box
- 1 bottle or container of CANNA CALMAG AGENT, from 1 to 10 L depending on the capacity chosen
Ratio, dose, conductivity thresholds, procedure and storage based on canna-uk.com, canna.fr and the CANNA instructions. Aquaponics: FAO manual and New Mexico State University.
Manufacturer and product safety
- Website
- www.cannagardening.com
Information provided under Regulation (EU) 2023/988 on general product safety.
Documents & manuals
CANNA deficiency guide
Recognising a calcium or magnesium deficiency before correcting the water. Manufacturer's document, in French.
Document not showing? Some publishers block display inside a frame, so open it in a tab.
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Frequently asked questions
6 questions
6 key questions
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