nutrient problems

AND ALSO IM GETTING YELLOW KIND OF COPPERISH COLORING ON LEAVE JUST SWICH IN 12/12 I BOUGHT SOME NEW NUTRIENTS CALL STARDUST HYDROPONIC NUTRIENTS ITS COMPLETE WITH EVERY THING IN ONE MIX ANYONE HEARD OF IT and my nute level was 444 at 2 month and when i raise it to 900 started turning colors what happening

How big are your plants? Your plants should be a couple feet tall if you want to give them 900ppm, and they should be growing really fast.

about a foot almost but kinda wide