CMX is cal/mag/iron additive used for preventing nutrient deficiency symptoms. Unlike other brands, CMX also contains all trace elements (Fe, Cu, Mn, Zn, Mo, B).  Did you know most deficiency symptoms are due to trace element deficiencies? Deficiency symptoms are all too common in growing systems that contain heavy feeders, or suffer from lack of maintenance or poor quality water.  CMX protects plants against problems such as: Blossom-end-rot Upward leaf curl Withered flower/fruit set Interveinal chlorosis Stunted growth rates - CMX contains 6% calcium, 2% magnesium, 0.2% iron EDDHA (NPK 4-0-0) and all of the other trace element (copper, zinc and manganese as EDTA, molybdenum and boron).