Possible Phosphorus def. (lots of pics)

These ppp plants are about 10 days into flowering after vegging for ~30 days. They are under a 150w hps and anywhere from 125-250w of cfls. The temp in the room never goes above 86, and there is co2 supplementation in the room. I transplanted these plants after a ph soil problem about 20 days ago and they grew very quickly but lately they have slowed to a crawl. Only one of the plants shows significant new growth. Other plants grow slightly taller but the leaves dont really seem to get any bigger. Also the lower leaves have started to yellow and die (see first two pics) while some of the higher leaves have a whitish yellow tip to them. The plants look very unorganized with some leaves upside down and sideways. The steams on the leaves began turning purple 5 days ago but i have read that ppp can actually do this sometimes but they are all doing it. Thanks for any help and my camera kind of sucks but if there are other pics that could help let me know and ill get them quick.

plants are getting a bit of heatstress. and the slow growth may be cool temps at night. ?

What tells you that its heatstress?

the first two pics are heatstress man.