Wilted/purple stems and veins.. Help! Please

I have some pretty big alaskan thunderfuck plants in 100 gal smart pots, and they have all begun to turn purple at the stems and veins on the leaves. My ph meter went bad and i think i had phed way too low for a watering or 2 about 8 days ago, so i flushed real hard since with straight well water that is 6.4-6.5.
I am running pro-mix Hp
Does this look like a phosphorus deficiency to anyone?

I am lost and sick to my stomach over this, and cannot figure it out. Some of the other plants, now the train wreck is starting to turn purple also. The leaves are very wilted and were kind of turning upside down and to the sides on all of the plants.
I fed with botanicare grow/ liquid karma/ and calmag earlier today trying to fix this problem.
Does anyone have any ideas? I have pk boosters laying around, should i give that a shot? Any help is MUCH appreciated! Thanks

Forgot to mention that the growth has slowed a lot.

bro the purple doesnt look bad.. i got a grow op inside and im seeing the same thing in some of my plants. it doesnt seem to be anything too major. but you never know! im gunna keep a eye on this post!

Thanks man but they are getting worse and worse, and they def arent looking half as happy as they were..
When the thunders are happy all the leaves are sticking up and no wilt what so ever.. The more i read, possibly a N deficiency?

hmm.. piss is rich in nitrogen i hear? Dilute some in ur water lol