Having a def problem and need a little help

Ok for some reason this round I have been having a big problem, started from clones and everything was looking great till they got about a foot or so tall then they started looking like the pics I am posting. The have pretty much stopped growing the stock and stems turning purple even the veins in the leaves are purple. They are also droppy like there not getting enough water and leaves look really puffy not flat and this is new and old leaves. I have had my ph at 5.8 water at 68 degs.(water chiller) room temp is 80 light cycle is 18/6 using dyna grow for nutes with ro water. I have flushed and new nutes several times. I was thinking a cal/mag problem sense I wasn't using cal/mag additive with using ro water but tried adding that and it hasn't seemed to work I'm at a lose here not sure what the deal is.

Why is your ph at 5.8?, looks to me that they are in soil, if so your ph so be 6.0 to 6.5 ph, that's to my understanding, at least it looks like in soil, am I wrong?

they need some cal/mag at least. why are so many leaves screwed up?

Dont think those are his plants as he said "then they started looking like the pics I am posting" and he's using a water chiller so.

No they are not in dirt there in a ebb&flow bucket system. Like I said tho with the cal/mag they have been flushed a couple times and replaced with fresh nutes with cal/mag added and nothing, they don't seem to want to get any better I'm at a lose. This is not my first time ether been doing it for years and never have I had this kind of problems can't figure it out for nothing.

and for the question on y is there so many leaves messed up, well they just started looking messed up and keep getting worse no matter what I do so not sure what's going on.