To buffer coco coir for optimal growth, you'll need to charge the coir with a calcium and magnesium solution. This procedure helps to stabilize the coir's cation exchange capacity and balance its nutrient-holding abilities. To make a buffering solution, mix a calcium magnesium supplement following the manufacturer's instructions with water. Then, soak the coco coir in this solution for 12-24 hours before draining and rinsing it with fresh water. After buffering, your coco coir is ready to use in your hydroponic system.