Nute Burn?! NEED HELP!

[Stix]

I HAVE A PROBLEM!!!! Looks like 2 of the plants are getting nute burn. I'm not sure cause I've never seen it before. the bottom leaves on 1 is turning blotchy brown. when i touch it it cracks. the other is the same. I do have the biggest and nicest plant right next to those with no probs at all. "YET". Here is the detailed info

Water Temp 78 F
Air Temp 80.5 F
Humidity 45 percent
PH 5.8
Nute PPM 850
using 12.5 ML FloraGro - 7.5 ML FloraMicro - 2.5 ML FloraBloom PER GALLON

Only thing that happened out of the ordinary was nute increasment. and leaving the nute sprayer on 24 hours tuesday and thursday which shouldnt be a prob according to the hydro store. I like to turn on and off in cycles to promote root growth which the hydro store recommended.
Alot of the roots are swimming in the nute solution. Solution is only about 4 inches below bottom of plant holders. Which is where it has to be. Here are some pictures.

 

[wakeandbake]

why are u going by ML when your mixing gallons..?? right now u should be using like 2tsps of florogro 1micro 1 bloom

 

[Stix]

that's what the directions say to use for the grow stage.

Someone else said this may be the prob

(quote)

It's not nute burn your suffering from my friend, it looks to me like your suffering a magnesium deficiency. If it was nutrient burn then just the tips of the leaves would be turning brown, not inbetween the veins like yours are.

You haven't mentioned whether you have added any Epsom Salts to your nute mix, I would highly recommend that you add some to give your plants a good magnesium boost, read the packaging to attain the correct dosage for your system.