IM Getting YELLOW fever!!!! HELP

i have my plants in an aero system. 3
Using Voodoo juice only
there in 1month 1weeks flowering.
400watt hps
temp-75 constant
1st time hydro grow

MY PLANTS JUST TURNED BRIGHT F&^(%&%ING YELLOW HELP!!

I checked my ph on a leave in tank meter and i was about 8!
very high! But what i did differently to get that ph was i just flushed the system and put in 30ml of juice.(i have a 1 gallon resv.) Which is what it recomended. The whole time ive been just dumping in the stuff without measuring! This time i put in nothing and the ph goes crazy. I just ordered a ph meter and a measuring cup-lol

heres the question, once a leave goes yellow....is there any going back? or am i screwed....

anyone?!?!!?

lower the ph.....when u were adding shit it raises the acidity....when u dont, it'll go high n make ur shit do all sorts of things, like turn yellow