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. Maybe your system isn't thoroughly soaking your plants possibly a lack of pressure. So not enough solution is running through to flush as it feeds meaning maybe you have build up of salts too quickly. Just a though check your pots for residue.
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.
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.