주요 사실

• Most common cause: pH outside the optimal range (5.5–6.5 in hydroponics)
• High EC can create osmotic stress that prevents water and nutrient uptake
• Mineral antagonism: excess calcium blocks magnesium; excess phosphorus blocks zinc and iron
• Symptoms mimic deficiency — yellowing, curling, or discolouration — despite adequate nutrients
• Fix: flush roots with pH-balanced plain water, then reintroduce nutrients at correct pH and EC
• Prevention: test pH and EC daily; change reservoir solution every 2–3 weeks