Leaf Curl problem - pictures and info included. Does too much CO2 cause curl?

Hello!

I am currently growing LA Conf and master-bubba. Im having a curl issue with the LA. Here is a few examples:

http://i52.tinypic.com/2v3h28o.jpg

&

http://i54.tinypic.com/nmjkhi.jpg

The master-bubba does not exhibit the curl. Example:

http://i51.tinypic.com/2arb75.jpg

There is a overall curl on the LA (with one or two plants out of 20 as a exception). I thought perhaps it was heat/lighting causing it as that has caused curl for me in the past. However after moving the lights away and cycling them with good room temps (74-79 canopy temp) the curl has not straightened.

I have CO2 running at about .75 in terms of release pressure @ 12 hour cycles. I have a fan that redistributes the co2 across the 10ft long canopy. Is that too much? The room is not completely air-tight so there is some loss that occurs.

Here is my nutrient schedule:
GH 3-part at recommended flowering cycle doses
50ml diamond nector
25ml cal-mag (I use a RO)
Great White

These are about day 17 flowering cycle.

I have applied Bush Master in first week of flowering (two water/cal mag flush cycles) and then half-nutes with MOAB about day 12.

The watering schedule has been very adequate with no over-draught. I hand-water every other day, 3-gal buckets with PH around 6. The soil gets near-dry after 48 hours.

PS- The 'spots' you see are not thripes but milk residue. I gave it a try last week with a 25% milk/water mixture. Im looking for a really helpful addative to make the milk spot-stains not exist. Will baking soda help? Looking to spray weekly until about week 5-6 of bloom.

Any thoughts would be helpful.

Thanks

Kind of hard to see the color with the hps on, but they look really dark green. Too much N can cause that leaf curl.

Plus with a canopy temp that low I don't think the CO2 is really helping much...
http://boards.cannabis.com/advanced-...ent-guide.html

ph of 6 is pretty low, assuming you are in soil? Same thing goes for watering every other day, maybe a bit too frequent for soil (but I don't really know much about your environment).

Different strains will have different needs (even the same strain in seed form, if they aren't stable genetics). Gotta figure out what each one likes and treat them accordingly. Some drink more water and like more nutes, others don't.

I know you touched on some of the information already, but filling out the copy-and-paste troubleshooting form here will help out a lot. The more detailed information, the better. :thumbsup:

troubleshooting form pls
could be a N def root bound when was last re-pot. Unless insect damage has occurred or the plant is suffering from a severe case of calcium deficiency, the plant is trying to tell you that it is water stressed. It's hard to tell exactly what the culprit is,

troubleshooting form pls

when did u transplant to the 3-gal pots? are they rootbound?

use a small amount of dolomite lime to raise the pH just a tad. as bigtops mentioned, 6 is a bit low..

although a 3 gal pot drying out in 48 hours is definitely possible, it seems a bit fast. id make sure that even the very bottom of the pot is dry before your next water.

i recently had the same problem as you (similar symptoms at least) and as soon as i did all these things my problems disappeared. hope this helps..

-pskunk