I think your method of dwc is different from mine. I don't know whats the best way to fix your situation. but I do know the problem is too much nutrients and too little oxygen.
My version of dwc is simplified consists of a bucket, airstone, netpot, water filled to inch below the net pot. The air stone aerates that water so the roots can stay submerged nutrients is added weekly not 5 times a day and is monitored purely on intake or lack thereof. It looks like you took a complicated way.. and you might regret that I am sorry bro! No one is helping because I don't think there is much we can do on our end. Your problem is flow both air and nutrient the claw is a combination of to much nutrients and too little oxygen. They are definitely not under watered because there is no wilt, you are over watering them and if you are watering the right amount of times as is suggested for your type of hydroponics then clearly they your feed has too little oxygen in it and the plants are drowning with each feed.
See for me it was the same, except soil so my soil wasn't draining quick enough which cause my soil to stay moist which means...less oxygen available at the root zone causing the droop plus, the fact that my stupid choice in substrate allowed nutrients to linger in my soil for too long causing a spike in N which started the curl. My plants looked like yours but my soil was easier to correct than your elaborate set up.