some badly curling leaves, not sure what's up

[WhiteWidow]

Hey guys, have some fairly healthy plants, although this grow got way big (plants are just over 6' tall), and I have a couple of them that are showing some bad leaf curling at the top of the plant that I've never seen before. I'm keeping my ph around 6.7 -7.0, growing in soil, under two 1000w hps. Using SensiBloom A/B, BudCandy, and Carboload. Staying on a regular watering schedule, thought maybe because the plants were so tall that the top leaves weren't getting enough moisture, flushed the soil a couple of waterings in a row, no change. Any thoughts?

Also.. if you look at the pic... look at the surrounding leaves, they look good and healthy. I'm about 3 weeks into flower.

[TBuds]

A lot of times it's to much nitrogen carried over into the flower cycle, they should b sum what lacking of Nitrogen wen going into flower. Causes no problem and the leaves dont recover,,but all is good she's jjust that 1 that needs a bag over her head,,u know that date u dont tell ur friends about