if its hot the plants can keep up with water alone but they take up water at such a rate that when you add the slightest amt of nutes you get that curl up real bad.. I had to move plants inside and dial down my centeral A/C to keep temps below 80F.. then and only then did they start responding with just a little curl up @ 1/6 strength nutes.. a week later I went 1/2.. same response.. but leaves got better in a couple days.. a week later I went full strenth and I havent seen any signs of added stress yet.. although just when I thought I was the hydroponic master I was folar wattering today and noticed creepy crawlies all over the leaves.. not sure what they are yet but fuckin hell.. can I get a break already? jeez

get a thermometer and find out exactly.. that temp is too close to guess.. since it could be whats causing a problem

oh and humidity.. if its super dry.. bad.. thats the other thing that turned mine around.. a cheap ass humidifier to keep the air moist.. that means less water used by the plant