Pro Cal by Green Planet — Cal-Mag Supplement for Coco, Hydro & RO Water
GP-NUT-PROCAL-1L
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Pairs well with
Pro Cal is Green Planet's Cal-Mag supplement — a 2-0-0 shot of readily available calcium and magnesium, backed by chelated iron, zinc, manganese and boron. It builds strong cell walls, drives chlorophyll and photosynthesis, and heads off the deficiencies that stall growth. If you're running coco, hydro or RO/rainwater, it's not optional — those setups start short on calcium and magnesium, and Pro Cal fills the gap at every feed.
Specifications
- Growing in coco or on RO/rainwater? Run Pro Cal every feed from day one — those media and waters start with almost no calcium or magnesium, so deficiencies show up fast without it.
- Add it to the tank first, before your base nutrients, and never mix it into concentrated feed — calcium can react and drop out of solution.
- Check EC and adjust pH last, once everything's in.
How to Use Pro Cal
Pairs Well With
Green Planet's base nutrient — Pro Cal tops up the Ca/Mg your feed doesn't fully cover.
GP3 GrowVeg base of the 3-part — run Pro Cal alongside it for strong early structure.
Coco CoirGrowing in coco? Pro Cal is the cal-mag it needs from the first feed.
Frequently Asked Questions
Do I need Pro Cal if I grow in coco?
Yes. Coco holds onto calcium and magnesium and starts low on both, so a cal-mag supplement is essential. Run Pro Cal every feed to keep your plants topped up and avoid deficiency.
Can I use it with RO or rainwater?
Yes — those waters carry almost no calcium or magnesium, so Pro Cal is exactly what they need. It replaces the Ca/Mg your plants would otherwise get from tap water.
When do I use Pro Cal in the grow?
Yes to all stages — run it at every feed from early veg through bloom at 1.25 mL per litre, then stop about a week before harvest as you head into flush.
Will Pro Cal work with my other nutrients?
Yes. Add it to fresh water before your base nutrients, mix thoroughly, and don't combine it with concentrated feed — calcium can react and precipitate if it's not diluted first.
What deficiencies does it fix?
Calcium deficiency (tip burn, browning crunchy leaf edges, weak new growth) and magnesium deficiency (interveinal yellowing and rusty spotting on older leaves). The chelated iron also supports chlorophyll and enzyme function.
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Cal-Mag Your Coco Can't Do Without
Chelated calcium, magnesium and iron for every feed. Free shipping over $499*.