Leaf edges folding upward?

Hoping there sombody that can give me a hand w/ my problem. My leaf edges curling upward. I was thinking mabe I should start watering a second time during the light cycle. I've checked my cubes after 8 hrs and there still seem pretty moist by the next day though there pretty dry. Thanks in advance :)
I'm curently feeding per. gal (25% run-off to waste)
Micro: 3 ml.
Bloom: 5 ml.
grow: 2 ml.
floralicious bloom: 5ml.
kool bloom: 2.5 ml
cal/mag 2.5 ml
res. ppm about 975
Indoor
hydroponic
-4" on top of 8" rockwool cube
--hydro drip
-Anything you have added to the soil
- rockwool ph 5.7 to 5.8
-R.O
-20 gal. resovoir/5.5
-5 wks (first wk of flower)
-GH 3 part/ plus floracious and cal/mag
- Dripers feed 2 cups per min for 2 min. once a day. this gives me 25% runoff. (per plant
-1000 watt ultra ace hps about 2' from canopy
-77 deg. day/ 69-71 deg. night
-35% Relative humidity
-12/12 Lighting schedule
-Air is exchanged about every 30 seconds.

1000w at 2feet should be safe, but the curl could still be from a very slight heat burn.

move the light up 2 or 3 inches and see if anything changes.

also....

1) forgot to commend you on filling out all your details of the grow. thanks a ton!

2) your ppm (975) is much lower than others i have seen on the site (1200-1500). I have absolutely no hydro experience, but was wondering if this is noteworthy and if there even is an advised ppm?

Yea i was thinking it might be that i started to run out of vertical room. thats why i did mission impossible lowering my trays and moving res. Either that or increase feeding, mabe salt is starting to build up? I'ts been a couple wks since i have done a flush. I think i might feed plain water once and raise the light a few inches.

Well this is my first grow using lower ppm values also drain to waste. except for my leaf edges everything is going great. My stalks are already over an inch wide. I have heard that the Lucas formulas works well. I'll have to post my results.

sounds good. your pictures didnt really show the entire plant,however. if it is heat related, it should only affect the tops of each plant (unless the room itself is too hot).

flushes are always good. doubt that its your problem, but theres no real reason not to give it some freash water to clean it out periodically. I also heavily mist my vegging plants to mimic rain during flushes. (dont mist flowering plants though, it may induce rot)

also, dont bump up ppm because of what i said. i have no hydro or ppm experience, and was just curiousity. :hippy:

Think about flushing your system thoroughly.....sounds like a ph or fert build up issue.

I use Clearex to flush every 2 to 3 weeks. I doubt I really have much of a problem with buildup since I always have at least 20% runoff and I feed,water,feed,water etc..

I can't tell if that is the light or your plants are a bit pale (=hungry).

The leaf-edge problem is caused by having high heat compared to your humidity. While your room temps look perfect, your canopy temps may be slightly higher, and your humidity is on the low side. Raising the light, adjusting your watering schedule, and increasing the relative humidity to about 40% should help a lot.

Otherwise, you have some nice healthy plants there.

Here's a picture of current ladies and a macro i took from previous.

Those are LOVELY! :thumbsup: