My ladies are doin' the twist!

Hey all, just wondering if anyone can help me diagnose this.

This is my veg room, 2 strains (arjans ultra haze #1, cheese and "sprucezeus" a sativa indica hybrid originally from bagseed i've been growing for a while.) For the last couple weeks, 5 or 6 of the plants' leaves have been twisting up and gettin' all curly and gnarled.

Heres a closeup!

Other than the crazy shit in question they are very healthy plants.
400w MH running 24 hours
between 22 and 25 celcius all the time.
60% humidity
Promix HP soiless mix. (recently switched from sunshine #4, i was told they're the same thing, but maybe this could be the culprit?)

Holland Secret line of nutes, i pretty much use their (FHD) products exclusively, they're inexpensive, work great, and my local hydro shop stocks alot.
I water them when they get dry (usually every 4 days or so) with settled 7.0 PH tapwater and feed every 2nd or 3rd watering with half strength nutes.
I've tried flushing them and it doesnt seem to have helped my problem.
Could this be a ph issue? (i dont have a soil tester)
I've heard that both promix and holland secret are within an appropriate range and i've never had this problem before.
I cant imagine that its a nutrient deficiency and they certainly aren't burnt.
WHATS GOING ON????

Heres a shot of my flowering room just for the hell of it.

nothing at all?

I gotta bump this one, I flushed the gals affected with ph6.0 water this morning so i will be closely monitoring them.
Anyone have ANY input?

could be too much ferts/nutes. or low humidity. either can cause those symptoms of wrinnkled new growth. dial back the nutes a bit and try feeding with ph water closer to 6.5-6.7 and measure the runoff ph and post results.

Just wanted to update and confirm it was in fact a ph issue, i bought some good strips and ph down and got things under control, those plants are happily flowering now.

ooo are there in advantages in use the half a sphere hood?? Your rooms look pretty big to only be powerd by 1000 watt can i get the diminson of your room?? Just curious

greenleafhigh said:

ooo are there in advantages in use the half a sphere hood?? Your rooms look pretty big to only be powerd by 1000 watt can i get the diminson of your room?? Just curious

Click to expand...

Shmeh, not so many advantages in my case, just what i had on hand. If i had a stadium style grow it would be more appropriate, what with the vertically hung lamp...
My room is 6'6" by 6' and the light does pretty well, not the best penetration for 1000w hps but the spread is pretty decent, i imagine i'll be investing in an air cool reflector soon enoughand tearing down and rebuilding my room larger, theres not alot of space to work in there as you can probably tell. Feel free to check out the link in my sig, i think thats the thread i go into detail about the light in.

Looks to me like PH is off.
Nice grow