Some white spots and Browning on a few leaves

Well a good month into grow and im noticing white spots and a couple rather large brown spots on the edge of one leaf and in the middle of another. I'm feeding it 7-6-7 Dyna Grow every 4-5 days with regular water (reverse osmosis water) every 2 days. I heard the white spots has something to do with the Cellulose but i'm not sure about the brown spots, just to be safe I sprayed it with a mixture of Hydrogen peroxide and water (about 1/15 peroxide/water mix) just to be sure it wasnt a fungus, and ive been spraying it with a "Garlic-Water" spray for about 3 weeks now to get rid of those damn mites (got rid of em, and they havent returned).

The affected leaves are on the lower part of the plant, more specific the lowest part and second lowest. The top 2 sets are fine but right below that I see white spots.

Thanks for any help.

sounds like the browning of the leaves is either from heat or possibly ph level but the leaves usually turn yellow. Hope this helps.