Is this a Magnesium deficiency? Newbie Needing advise !

Okay This is My 1st attempt at growing. I'm sure everyone is sick of newbie questions, but i just have to ask . is this burn or Magnesium problem or neither ? any advise would be appreciated ....


Indoor Grow

3 1/2 gal pot
70/30 Mg organic potting soil and perlite
l18/6 250w hps
water ph from tap 6.8 and ppm is 20-30ppm
temp 70's f - 80's
when adding water soluble fert water ph always adjusted to 6.8 and ppm reading about low to mid 800's after fert is added .

You can go lower on the PH. 6.6 is ok, but to tell you the truth your plants look just fine, I have yet to grow any plant that didn't have a few leaves that looked like that, its very normal and I highly doubt it affects your overall plant yield. The only thing I would do is add more light and make sure I wasn't watering too much.

Thanks for your response... I hear ya with the bigger light but unfortunately the 250w hps was all I could afford when I get ready to flower I have a bunch of 2700k cfls I plan on adding in there, it may not the most efficient way to go, but I have to work with what i got. and I let it get pretty dry before I water about 4 days apart or when the pot is light easy to tell by lifting...
I was just concerned when I noticed the veins where turning brown and spreading out plus the leaf tips where getting white it looks like it was working its way up from the bottom of the plant I just didn't want to let if go to far if there was a issue that needed correcting..
Thanks again for responding ....