Plant problem please help!!!

[Dellamorte]

Hello all!
This is my first time growing cannabis and I am having a problem with my plants. I'm 3 weeks into growing my 9 Super Afghans in Promix soilless mix, I currently got them under a 400w Metal Halide conversion bulb on 24/7 schedule and a temp of about 85-89 also I started them on a 1/4 strength nutrients about 10 days ago. For the last few days I have been noticing some of the leaves on about 4 or 5 of my plants starting to show spots and discolorations, some of the marks on the leaves look like nutrients burn but im not sure about others maybe a deficiency of some sort. I took a couple pics of the plants that had the worst marks the others are pretty minor but im worried they will get worse.

http://img481.imageshack.us/img481/7192/img1461ns2.jpg
http://img75.imageshack.us/img75/5098/img1458uq9.jpg
http://img75.imageshack.us/img75/6310/img1467wz0.jpg
http://img481.imageshack.us/img481/8478/img1474oo5.jpg

[dusto2k3]

are you using r/o water?

are you adjusting the ph of your feed before

[Scarlet Sky]

looks like the start of a calcium deff...

[stinkyattic]

Get some calmag+ into your feeding schedule
Check your pH... you could have a lockout... and that soil looks swampy=bad combination
Lower your temps to under 80F.

[Dellamorte]

Hello again to everyone!
Thank you for all your feedback.
Since my last post I have made a few changes, I put the lights on a 18/6 cycle and lowered my temp to 79-85(its the best I can do), my light is now 15" from the top of the plants and I repotted them in 1 gal bags.

In reply to all your suggestions no I am not using r/o water, I have been using distilled bottled water but have just switched to tap water.

After watering my plants I ph tested the runoff and it was 6.0.

Now about the calcium defiency I consulted my local grow shop for some info and they told me that there are small levels of calcium and magnesium in the nutes I am using so a defiency MIGHT NOT be the problem but they thought that I might have been underfeeding my plants so I fed them.

They look much greener (sort of) but the problem I am having now is that they seem to have stopped growing, the leaf tip are curling up and down, and they are looking a little crispy.

Is this nute burn or another defiency?

http://img241.imageshack.us/img241/9537/img1543et2.jpg
http://img241.imageshack.us/img241/8383/img1544ss5.jpg
http://img489.imageshack.us/img489/259/img1577mt1.jpg
http://img337.imageshack.us/img337/4431/img1567wr8.jpg

[iblodro4220]

flush em and see what you get

[stinkyattic]

With a runoff pH of 6.0 your plants can't uptake nutrients properly anyway, so you have to fix THAT problem before adding more nutes, or you are just wasting fertilizer... Get your pH up to around 6.7, keep on with the tap water, but you have to adjust the pH so that the plants can use what you give them.