Veg+Bloom - Stax (AKA Stackswell)


Size: 2.2lb
Sale price£72.99

Combined Cal-Mag, Wetting Agent and Drip Cleaner

Stacks (formerly known as Stackswell) is a special blend of humic acids, calcium, sugars and magnesium, incorporating multiple products into one powder. Hydroponic Research nutrients are powdered nutrients formulated for growers operating at huge scales, where tiny differences in performance have huge pay-offs. They're designed to squeeze as much as possible from your plants, which explains why customer feedback on this range has been exceptional.

Calcium and Magnesium

Calcium is an essential nutrient, playing a vital role in many physiological processes. Among other things, calcium is involved in cell wall formation, cell division and expansion, and enzyme activity. A lack of calcium can lead to stunted growth and a number of other problems, including blossom end rot in tomatoes and peppers.

Magnesium is another essential macronutrient for plants. It is involved in photosynthesis, chlorophyll production, and the synthesis of ATP (adenosine triphosphate, the energy currency of the cell). A lack of magnesium can cause yellowing of the leaves (chlorosis), and in severe cases can lead to death.

Humic Acid

Humic acid is a complex mixture of organic acids that are produced by the decomposition of plant and animal matter. Humic acid can improve the physical, chemical, and biological properties of soils. It can increase a substrates ability to hold water and nutrients, improve drainage, and reduce compaction. Humic acid can also increase the activity of microorganisms and help to release nutrients from organic matter. It acts as a chelator, converting nutrients into readily available.


The above mentioned ingredients work synergistically with the sugars to increase photosynthesis rates and improve nutrient uptake. The sugars provide a source of energy for both the plant and the beneficial microbes in the substrate.

Visit the Veg+Bloom category to see the complete range or check out the One Stop Blog for more info.


Choose from 1lb (453g) , 5lb (2.275g) and 25lb (11.36kg) sizes using the dropdown menu.


  • Formulated with a blend of humic acids, calcium, sugars and magnesium
  • Speeds up growth rates, for bigger and better plants
  • Multiple products in one powder
  • Increases nutrient uptake and drought tolerance
  • Teams up nicely with the rest of the Hydroponic Research range
  • Perfect for all hydroponics systems as well as coco coir and soil
  • Made in California

How To Use

A copy of the Veg+Bloom feed chart can be found in the downloads section, which provides information on dosing.

You'll need a pH meter and an EC meter to administer these nutrients. You can find a large selection of suitable equipment in the pH & EC Control section.

As always, add one nutrient or additive and give the reservoir a good stir before adding the next one.

Early veg: bring start water to 0.2 - 0.3 EC

Veg / early flower: bring start water to 0.2 - 0.3 EC

Flower : bring start water to 0.2 - 0.3 EC

Change your reservoir out at least once per week.

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