With Coco, it is important to consider the exchange of ions that happens whenever fertigation is applied to the media. At lower use rates the plants may use up all the available elements applied with other elements unused leading to an imbalance in the Coco in the future. Some Ions persist in the Coco more than others due to their CEC and rate of uptake/immobilization. At higher use rates, the ions in the soil solution may impede the uptake of others. 

It is important to flush (especially if plants are hand watered) in Coco periodically, and if the plants are being watered, the runoff water must be allowed to drain away as waste water. Coco problems usually stem from overaccumulation of junk from wastewater or an imbalanced or overfed media solution. Always calibrate pH probes before use when mixing any nutrient solution.