CalMag Pro

The perfect base for RO- and soft water

A shortage of calcium and magnesium (Ca/Mg) in reverse osmosis (RO) water and soft water is a well-known problem. CalMag Pro ensures that a balanced concentration of minerals is available in the water. This is the perfect base to start creating your nutrient water. CalMag Pro is mainly used with RO water and soft water.

CalMag Pro contains the optimal calcium and magnesium ratio to prevent competition between the two nutrients. Some magnesium and calcium fertilizers are not mixable due to sulphates, but CalMag Pro contains both elements in perfect proportion.

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With LED lamps, plant transpiration is lower than with traditional lamps. This disadvantages the absorption of calcium and magnesium. By adding CalMag Pro, you compensate for the reduced transpiration.

CalMag Pro strengthens cell walls. By connecting different essential molecules, the plant gets a rigid structure that improves resistance.

The use of CalMag Pro promotes young root growth, allowing the root hairs to absorb nutrients more efficiently.

Detailed info

Dosage and use

Shake well before use. Add a maximum of 1 ml CalMag Pro per liter water (1:1,000). Use this solution each time the plants are irrigated.


NPK fertilizer (5-0-0).
CaO: 5.7%
MgO: 3.3%


500 ml & 1 L bottle and 5 L, 10 L & 20 L can.

Some sizes may not be available in all countries.

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Want to create a custom grow schedule with CalMag Pro? Start right away!


We recommend a quantity of 0.75 ml per liter of RO water to achieve an ideal starting EC of 0.4.
Got questions about CalMag Pro? Ask our Grow Experts!
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