BioBizz CalMag is a calcium and magnesium supplement designed for growers who need extra Ca and Mg because of soft tap water, reverse osmosis water, demanding growing media or a visible deficiency.
Calcium and magnesium both play important roles throughout plant development. Calcium supports healthy cell production and plant structure, while magnesium is essential to chlorophyll and photosynthesis.
BioBizz CalMag gives you a simple way to supplement these essential elements without changing the rest of your BioBizz feeding programme.
It can be used during vegetative growth and flowering in soil-based substrates, coco and hydroponic systems, either preventatively where your source water is lacking minerals or as a corrective treatment when plants show a genuine Ca/Mg deficiency.
Not every grow needs extra CalMag.
If your tap water already contains enough calcium and magnesium and your plants are healthy, adding more unnecessarily can create problems rather than solve them.
However, growers using very soft water or reverse osmosis water can start with little or almost no background mineral content. Some growing methods, particularly coco, can also increase the importance of keeping calcium and magnesium availability properly balanced.
BioBizz CalMag is designed for exactly these situations, helping you correct your starting water or deal with an actual deficiency without rebuilding your entire nutrient programme.
Calcium is involved in cell production and structural development. A sufficient supply helps support healthy new growth and strong plant tissue.
Magnesium plays a central role in chlorophyll, making it particularly important for photosynthesis and healthy green growth.
When either becomes deficient, plant development can suffer. The right CalMag supplementation helps maintain the balance plants need without simply increasing your base nutrient strength.
One of the main reasons to use BioBizz CalMag is poor mineral content in your source water.
Soft tap water can contain relatively low amounts of calcium and magnesium, while reverse osmosis water has had most dissolved minerals removed.
If you are using RO or very soft water, BioBizz recommends CalMag as part of your regular watering programme to replace these missing elements.
Add CalMag to your water first, mix thoroughly, then add the rest of your BioBizz feeds and additives.
CalMag can be especially useful in coco, but it should not automatically be added heavily to every coco feed.
Coco can create a higher demand for calcium and magnesium, particularly when combined with soft or RO water. BioBizz specifically notes that some demanding coco grows may benefit from additional Ca/Mg supplementation.
Use your source water, plant response and feeding programme to decide whether extra CalMag is actually required.
BioBizz uses different rates depending on whether you are preventing a deficiency caused by RO or soft water or correcting an existing Ca/Mg deficiency.
| Stage | CalMag |
|---|---|
| Early Cycle | 0.5ml/L |
| Mid Cycle | 1ml/L |
| Late Cycle | 1ml/L |
| Stage | CalMag |
|---|---|
| Early Cycle | 0.5–0.8ml/L |
| Mid Cycle | 1–1.4ml/L |
| Late Cycle | 1–1.4ml/L |
| Stage | CalMag |
|---|---|
| Early Cycle | 0.3ml/L |
| Mid Cycle | 0.5ml/L |
| Late Cycle | 0.8ml/L |
| Stage | CalMag |
|---|---|
| Early Cycle | 0.3–0.8ml/L |
| Mid Cycle | 0.5–0.8ml/L |
| Late Cycle | 0.8–1.2ml/L |
*Use the prevention rates when supplementing RO or very soft water. Use the deficiency-correction rates only where additional calcium and magnesium are genuinely required. Always monitor plant response and the overall strength of your nutrient solution.
For a straightforward full-cycle BioBizz programme, use CalMag alongside our BioBizz Complete Soil Nutrient Kit.
The kit gives you the core BioBizz feeds, boosters and additives needed through growth and flowering, while CalMag provides additional calcium and magnesium support where your water or growing method requires it.
It is especially useful if you're starting with soft or RO water and want your whole BioBizz programme covered from the start.
Don't add CalMag just because it's part of the cupboard. If your water already contains enough calcium and magnesium, your plants may not need any extra. Use it where it earns its place — particularly with RO water, very soft water, demanding coco setups or a genuine Ca/Mg deficiency.
How often should you use this in a soft water area?
For soft water usage, we recommend using Biobizz Calmag from first water to harvest, unless you are using this in a Coco medium where you should use this Biobizz Calmag throughout.
YOUR LOCAL HYDROPONICS EXPERT
Covering the Midlands, Bristol and London, whichever of our shops you visit, we can guarantee you'll get the best price and unbeatable advice from our expert staff.
