Is this a P defficiency?

Hi, I have some clones (6x Blue dream, 6x Blue oddyssey) They were put into veg about a week ago.
Cutting Edge Solutions Nutes, 400ppm

FYI, they were at 5.3 PH for at least two days. Could this have locked P out? I have since upped it to 5.8. Leaves are drying up and dying from the edges and tips inward until the whole leaf dries up and dies.
Even the new growth is jacked up on the tips.

here are some pics.

that looks like nute burn

Thank you for the reply. Ok, will flush for 24 hours. What PPM would you recommend starting back with? They are at 400 right now.

3 weeks later,, Update.
Plants are looking healthy. I dont think the roots have grown as much as they should have, but up top they look Nice, do these look about right for 1 month? (the smaller green crack have been in 18 days)

Would also like to ask, does anyone think I should be pruning these at all? I am affraid they will starty stretching if I dont. I topped them, and have been using LST to keep them short, so there are a LOT of tops. They look crowded. Should I wait until after the flip to start pruning, or now?

Also posted this question in the Advanced Cultivation forum