Can anyone give some advice to what can be happening?

Hello all, I have 6 plants of Phantom cookies and 6 Afghani going right now, approx. 2 weeks into veg from clones and they both seem to be suffering some sort of issue and any help would be appreciated. Here's a little of my specs....

Lighting: 600w MH approx. 24"inches from plants
Ambient Temps: Steady 72 degrees F, 30% humidity (basement grow)
Watering & Nutes: Every 4-5 days with 15-20-15 fertilizer and 2 oz. Cal-Mag per 5 gallons equaling approx. 900 ppm. PH at 6.0-6.5 (I try to keep my nutes simple and give all these plants the same thing and amounts)
Growing medium: Coco Coir
Pots: Phantom cookies in 3 gallons (at the moment) & Afghani's in 10 gallons

First issue is with the Phantom Cookies, I am having an issue with downward curling leaves.
Second issue is with the Afghani, There is brown spots occurring on every plants but not on every leaf and some of the leaves seem to be turning sideways? Also the leaves that have the spots are a bit on the crunchy side.

Any suggestions or thoughts? Thanks!

Peckerwood,
It's always good to assess your water situation as a first step. Tapwater? And what is the ppm of said tapwater. What are you correcting your ph with? And to what level?

I agree with DannyBlaze that your feeding could be high. I see no nutrient burns but you could be locking out Mg. You probably should flush just on general principles and drop nutes a bit. If you are using fairly hard tapwater...perhaps the extra Ca in calmag isn't needed. I prefer MgSO4 (Epsom Salts) as a Mg supplement since it has no extra Ca or N. So no definitive answers yet but am awaiting answers to questions...
JD

First off, thanks for your replies. As far as the water, I am using city tap water that has a PH of 7.0 and a PPM of 143 and I am correcting my PH with General Hydroponics PH UP/Down to around 6.0-6.5. This is my first run with using Coco Coir as I switched from Promix BX. The Promix seemed to hold alot more water and would not drain very well and would actually puddle on top. The Coco drains very well and almost too well and was worried that the nutrients just might be flowing right passed the roots and not being absorbed, so thats why I tended to feed a bit more I guess. I'm trying to feel the Coco out to see what I should be doing better. Another question is how many times a week should I be hand watering with Coco Coir compared to using Promix? With Promix I was watering the same amount per week which was every 4-5 days. What should I have my PPM at with nutes instead of 900?.. Maybe around 600? Perhaps skip out on the Ca-Mag period? Thanks again.

Peckerwood,
Your water situation sounds good. I'm no coco expert...used it a bit. There are various grinds available and it sounds to me that you have a coarser grind. Perhaps you should take a more hydro approach to your coco. That's what most of the experienced growers do. Drop the ppms, maybe 600ppm might be good...and then water daily. That would be much preferred to what you're doing by blasting them less frequently with a stronger feeding. And be sure to get at least 20% runoff when you feed. That's what I'd do...
JD