SH System, problem with 1 plant only

So, having an issue with only one plant in my sh system. One has these strange parts only on fan leaves between the veins. They are 2 and 1/2 weeks old, we have the nutes that are supposed to go with it. They are bag seeds so we aren't too sure what they are, and they are under 3 26watt CFLs, 2 65watt CFLs duel spectrum, and 2 wal-mart grow lights. They are all doing great, but this is affecting just the one. I am really curious because since it is in a hydro, I wondered why this was only happening with one plant. Please please helpf if you can! ( i was thinking zinc but its so odd its only one hurtin)

What is your ph?

sorry. the ph is 6.8

your ph is way to high for hydro, it should be around 5.8-6.0

not gonna argue but everything else has said 5.5-6.8 ish is fine though its pushing it, i did just introduce full strength nute for the first time but still its only that one plant out of 6 that looks like that...a few others have a few spots but nothing to fret aboot

Bring your ph down to 5.8. Anything over 6 is normally for dirt growers. How often do you clean your res?

we empty and refill it roughly every 10 days..The whole problem with this is we dont' know why only one plant is hurting. if it was the ph or a deficiency wouldn't more be hurting?

not necessarily. Bring the ph down flush everything out and hopefully it will clear up. I dont know other than that. sorry wish i could help more