• -6%


€11.07 Save 6%
Tax included

Cal-Max from Grotek is a calcium and magnesium additive for reconstituting reverse osmosis water, for deficiencies of these microelements vital in cannabis plants or as a complement to the fertilizer in coco substrates. Very easy to use, calcium and magnesium are combined in one bottle in the ideal proportions for reconstituting reverse osmosis water.


Ask a question (0)

Type and Use

This is a calcium and magnesium supplement for use in cases of deficiency of these microelements, to reconstitute osmosis water, or as a supplement to fertilizer in coco substrate cultivations. It can be used on all types of substrates and is compatible with all automatic watering systems.

Benefits for the Plant

Long-term watering with distilled water will eventually cause calcium- magnesium deficiencies. To prevent this problem, add an adequate dose of calcium and magnesium to the distilled water.

Calcium and magnesium are essential microelements for plant development. Calcium is involved in the hormones that regulate growth. It relieves water deficiency stress and provides stability to the cell wall. Magnesium is part of chlorophyll and is crucial for photosynthesis. With this product, it's straightforward to reconstitute reverse osmosis water and provide the cannabis plants with the needed calcium and magnesium levels.

Directions for Use and Dosage

  • To reconstitute osmosis water, measure the dose with an EC meter. Add Cal-Max until reaching a value of 0.4-0.6 mS of electrical conductivity.
  • If deficiency is detected, apply:
  • In soil and coco substrates apply 2 ml of Cal-Max per liter of water.
  • In hydroponic cultivations use 1.25-2 ml of Cal-Max per liter of water.
  • For foliar use, add 10 ml in 4 l.


 NPK 2-0-0

2% nitric nitrogen, 3% calcium, 1% magnesium, 0.1% EDTA chelated iron.

La Huerta's Opinion

This product is an additive, it should be used along with a complete growth and flowering fertilizer.

Data sheet

Growth stage
Type of stimulant or additive
Nutrtional complement
Type of grow
Aeroponic grow
Coco grow
Hydroponic grow
Soil grow

No customer questions for the moment.

Your Question has been successfully sent our team. Thanks for question!
Ask a question
hide form

You might also like

Cross Sell Products

16 same category products:


€11.78 €11.07