PH imbalance causing nutrient lockout. What is the PH of the water going in? Are you using RO water? On a scale from 1 to 10, 1 being dry and 10 being extremely saturated, where would you place yours?
Also, environmental specifications are critical to a proper diagnosis. Temps, humidity, light distance, light wattage, open/air cooled, etc...
The absolute last thing you need to do is throw more nutrients at it, though. I would add a rhizo supplement to PH'd RO water and let it sort itself out. A foliar spray with compost tea or rhizo would do wonders as well.