need help, early veg, DWC

hello, it's been awhile since i've been around this site, but i've found when i've had a problem before i got help real quick... so, here goes...

4 plants in DWC garden. fluorescent lights (for now), fox farm nutes... my problem(s) are this, for some reason the strongest plant's got sum discoloration going on. started on bottom leaves and seems to be moving up. one of the other plants was doing the same thing, but isn't discolored really anymore, just weeping and sad looking. i thought the issue was PH as i ran out of calibration solution for my tester, but recently i got some more calibration solution... the thing is, i got sum 7.01 (green) and sum 4 (pink), to calibrate my tester. when i stuck in the 7 and adjusted it, then rinsed and went to the 4 it read 3, but when i adjusted to the 4, then tried the 7 it read 8... not sure really what the deal w/that is, but got sum vinegar and apple juice to test as well and think the tester is good now. anyhow, what's up w/the discoloration? nute burn? how can it be fixed? also any idea why one plant is all weepy and sad looking, strain maybe?

Man, in this case id give them just water, or cut your mix in half them plants are drunker then red neck after 20 shots

you running 52 watt FL's? put them lights 2 inches about the heads