White spots and yellow leaves on bottom ? Questions from a first time grower !

Well, I would bet money the white spots are thrips. Neem oil or a water/alcohol mix should be effective. The yellowing is odd to say the least. It's a clear indication of nitrogen deficiency, but your mid way through flower and floramicro contains a hefty amount of it, so that shouldnt be a problem. I believe your solution lies in the pH. I would guess that your spil has become too acidic for proper nitrogen uptake. Check the runoff, if it's under 6, then the yellowing leaves would make sense. Do a flush (heavy if far below 6, light if its close). Hope this helps, this one was a real brain teaser!