Please Help! Troubleshooting form included

C=Answer if you grow coco
E= EVERYONE needs to answer lol!

E-indoor
E-coco
E-specific medium: coco/perlite
CSL-Soil type/brand: Readygro Moisture formula
SCL-Anything you have added to the soil: none
SCLR-Soil or slab runoff pH: 6.5
E-Water source: Tap
E-Source water pH: originally 7.5-8. PH Down to 6.5
E-Age of plant: 2.5 months
E-Type of fertilizer: Pure Blend Pro (organic)
E-Rate of application: feed once every other week. half dosage
E-Lighting source and distance from plant: HPS now 6"
E-Air temperature:75* lights off, max 80* lights on
E-Air % Relative humidity: 35%
E-Lighting schedule: 12/12 8p.m. to 8a.m.
E-Type of ventilation your room has: in a 2'x2'x4' homebox xs dayton exhaust, inline duct from a/c unit for intake w/4" can fan to boost cold air (it's hot here)
TR-Did you pre-soak your media in pH corrected solution: no

Okay, here's the deal folks. Please keep in mind I'm very new (my first grow) and all products used are recommendations from my local hydro shop, so hopefully he's not as much as a douchebag as he seems:

I have four plants: 3 fems, 1 male. One of the fems is having some strange leaf development. They are almost 2 weeks into flowering (started 6-14-09), the tallest lady started showing some leaf curling in a few of the lower leafs. This after watering with veg nute still.

The only thing I did up untill changing the light from MH to HPS on 6-20-09 was change the light cycle from 18/6 to 12/12. So basically I left the MH in for a week, and gave one more dosage of veg nutes this past Saturday. I also changed to HPS this past Saturday.

The fingers on the leaves are curling in from the edged turning into "tubes". Some were worse than others, but the upper leaves (half way up and up) seem ok. There is some discoloration (yellow-ish) on some of the curled leaves, but some of the curled leaves are still green. It's acting very strangely considering what I put into them. My watering schedule is about once a week...I've read to wait until the pots are dry a few inches down to water, and that's how long they take to get that dry. Every other watering I give half the recommended dosage of nutes. I water with balanced 6.5 water, and the runoff is the same as the input. I have not tested the PPM as I didn't have a tester at the time.

Birthdays are good to me though and my friend got me a Hanna 98129 tester. So being the eager beaver, I tested my tap's PPM and it was almost 600(590-ish). I was using his tester for PH balances previously. He has the pimptastic Hanna tester.

A little history: These plants were started in an Aero Garden and stretched A LOT. Maybe I should've LST'd this particular one. Other than the leaf problem, the plants seem healthy and took to the transition from the Garden to coco pots nicely. Nice thick stalks, longs fingers, etc. Other than this leaf problem there would be no indication that anything is wrong.

Tonight whilst I wait for some saint to reply and lend their expertise, I am going to run 6.0 PH water through them and flush thoroughly. Maybe they're under nourished? I don't quite understand the whole PPM logic yet. Don't know what it's supposed to be, what is too much or too little. I did read around here as much as I could, but could never find a definitive answer to what the plants like best growing in coco.

If pics are needed let me know and I'll snap some tonight.

Thanks in advance for any help everyone. It is very appreciated as I know how long this post is LOL.

****Almost forgot! The guy at my hydro shop said that coco will "assimilate" to what you put into it. So if I add 6.5 PH water, the coco will be 6.5. For shits and giggles I bought a cheapo $10 soil meter just to get some indication of the coco PH, it read between 8-7. Don't know how accurate that is, just thought I would throw it in.

*junk