Leaves curling/yellowing/some black spots on young plants

Alright guys,

Just placed these girls in their pots of hydroton after getting them from a local dispensary here in southern california. Over the past 3 days I've noticed they look like they are weeping a bit...most plants also have very mild leaf tips that are yellowing slightly and curling up dry. One plant in particular looks pretty stressed, he has the leaf issue on many leaves as well as black areas that are barely noticable on the leaves themselves, but as you'll see in the attatched pictures are quite distinct in the stem. Could that particular plant be diseased?

Hoping some experts can chime in. My readings/stats are as follows:

Advanced Nutrients A+B SensiGro
pH 6.5
ppm 825

Tent Conditions:
80-81 degrees farenheit
40-45% humidity

Oh, and the strain is G-13 in case anyone is interested!

Can anybody chime in...?

Over nuted id say. Give it pure water for a bit then bring ppm to 400 and if thats a hydro system ph should be lower around 5.5-5.7.

yeah for a dro grow it need to be lower for a soil grow ur shit is perfect

if this is hydro, that ph is way too high. Potassium gets locked out at 6-6.50. Looks like you have a ph issue. 5.8 would be best. also, they look a bit stretched-can you move the lights closer?
check out the pics here: http://www.ganjaguerrilla.net/index.htm
and here: International Cannagraphic Magazine Forums - The Complete guide to Sick Plants,pH, and Pest troubles!. The light green is either over fert or Nitrogen defecient. what nutes are you using and what type of setup/system do you have? DWC?

Thanks for the replies guys, I'm gunna try lowering the ph down to about 5.8 and hope that helps. Check out the stats in my original post but I'm using advanced nutrients sensigro a+B currently at 825ppm.

Britte says: "Over nuted id say. Give it pure water for a bit then bring ppm to 400 and if thats a hydro system ph should be lower around 5.5-5.7." that 850 ppm is just unnecessarly high. also they look a bit strectchy-can u lower lights?

If you are using soil grow how much ppm should you give on your 4th week of growing?

I agree with the posts above, ph too high, aim for 5.6 which will keep you under 6 in the root zone (once they are eating again that is) What's your EC, not ppms? If you can only read ppms then you will have to state the conversion factor i.e. Hanna/Eutech or Truncheon, otherwise your numbers are meaning less to us.

Good luck mate,
Unity