ive never had nute burn as long as ive been monitoring my ph and ppm, i think propper ph is key to not burning them, my grow room is very stable as well, i run my nutes as pure blend pro flower-1500ppm, liquid karma-100ppm, silica blast-100ppm, cal mag-100ppm, comes out to 1800ppm, but i am in my 3rd week of flower, its under a 1000watt hps, ebb and flow system, ph 5.6, 75F, 50% relative humidity, 72F res temps, 1000ppm co2, i'm growing blueberry and hindu kush, have you tried to raise your ppm's and gotten bad results? what kind of nutes are you using?