Just started flowering, and a deficency occured... just need help identifying

Just started flowering my girls and 5 out of 6 plants are showing the similar traits. Lighting is under 400 w hps with 8 cfl's as well. Temp hovers around 75 most of the day, Giving 75% strength nutes, 15-30-15. Only noticed this on the new growth of the plant since flowering. I've been flowering for about a week and a half. Any advice is appreciated!!! Just from what I have heard, I do think this may be Phosphorus deficiency. but thats my guess, just wanna hear from the experts! I also attached a picture and can provide more if needed.

Could be over watered? Not the right Ph?

It's not overwatering for sure, but pH probs could be right... anyone else have a thought?

what do you feed your plants and were does your water come from? whats your watering ph

my water has a pH of 6.8 and I have tested the run off and its usually around 6.5, right now i don't have the money to afford and EC meter, but planning to get one for my next grow. Is there any advice any of you can give me on how to fix this