B&Q - City Hydroponics Calmag Agent Calcium Magnesium Additive 1L

Canna

Hard water (EC>0.5) contains more calcium and magnesium than the plant can handle. When you’re growing plants, the best way to treat this kind of water is to use a reverse osmosis filter and then mix your hard water with the R.O. water, until you reach an EC level of 0.4.