Please help me id this problem and how to fix it. thanks

Alright my plants are about 2 weeks old, i have recently been seeing brown spots and brown lines in my plants leaves. I have been told its mag def, cal def and so on. I just now started using miracle grow all purpose food (little side of spoon per gallon, when i seen the spots about a day ago) i am using peat moss and perlite with a tad bit of mg organic soil. Watering with tap water and i dont know the ph levels sorry, pretty new at this. Should i just start using distilled water and flush them? I dont want them to die and im really not sure how long i have till they all die.

Sigh,,,,,The MG is going to be the problem soon. Ca sounds ,,,,, oh to hell with this.......

First off get a book on growing plants indoors....then move up to a book on Cannabis.

You should read this.
http://www.amazon.com/Marijuana-Growers-Handbook-Complete-Cultivation/dp/0932551467
Now read this to learn about soil and how it works and whats in it.
http://www.amazon.com/Teaming-Microbes-Organic-Gardeners-Revised/dp/1604691131

Here is a nice beginners water only soil you make.
http://forum.grasscity.com/organic-growing/1116550-easy-organic-soil-mix-beginners.html

Your soil or"media" is going to be a problem down the road......lacking needed supplements....

You need to add dolomite lime/egg shells and control the pH.
M Grow is not made for weed growing! It can work,,,,,search this site for growing tips for MG....

I don't mean to sound like an ass,,,,,but learning something about what you want to do before you started would have helped!

Good luck

Most soils are not suitable for cannabis indoor and mg soil is one of them. Yellow leaves brown tips and spots all over. Try some canna terra coco professional or something similar made for growing dope ,its perfect. The soil your using is ok for veges or roses outside. Try to start with the best medium you can find as you dont want to be behind the eight ball from the beginning.