Nitrogen Deficiency in Hydroponic Flood and Drain System

I'm having trouble with my system. My plants are showing signs of water logging and nitrogen deficiency and worsens after flush. I hear clearex helps with salt buildup, but I don't know if that's whats wrong. The leaves are starting to show sign of deficiency and are curling.

Those look like my leaves. But I definitely don't have a deficiency of any kind. How is the new growth?