What is this? Brown/orange spots (PICS)

[the big smoke]

This is my first grow. My plant has been pretty hardy thus far and has withstood my newbie abuse wonderfully. Now that I finally feel like I actually have a grasp of things, this started less than a week ago and has progressed to this point. It goes so slowly it is hard to tell if it has stopped or it is getting worse, so I thought I should start taking pictures, and then I thought I might ask you all for help identifying my issue.

What type of medium; soil or hydro? Hydro, 5 gal DWC
Indoors or outdoors? Indo.
What strain? F1 AK-47 x Purple Kush
How old are the plants? Sprouted from seed 27 July, so 74 days
What type of lights and how many watts? 224w CFL, mix of warm white and daylight
How far from the lights? tops at ~1-2 in.
What is your watering frequency and source of water? I use store-bought bottled distilled
What, how much and when was it fed? NPK? Botanicare Pure Blend Pro Bloom 30ml + Cal-Mag Plus 10ml + Cannaym 10ml (just ran out) all per 4L water
What is the medium/runoff pH and PPM if in hydro? 5.5-5.8 pH
What are the temps and humidity in the room? 70-80F, fluctuates with outside temp
What size pots? 6" net pot in 5 gal bucket
Any bugs? Look real close. I have looked for signs I know of and have found none.

[LowGrow]

It almost looks like light bleaching.
Or Boron defic..

Have you looked at your roots? Are they bright white? Any bad odor coming from them?

[the big smoke]

I looked at the roots. They are not bright white. They are mostly white and light creamy beige colored, and there is no foul odor, just the smell of the nutrient water. I have sporadically checked the roots throughout the DWC part of the grow and they have grown consistently and more and more have come through the net pot, but they have always been this color, which is similar in color to the nutrient solution.

[the big smoke]

It seems to be getting worse. I did a complete water change yesterday (save the last ~.5 gal which I can never quite drain completely from the DWC reservoir) this time using 30 ml PBP Bloom and 5 ml Cal-Mag Plus per 4L water. The tips of almost all the leaves on the plants are white, almost burned but very little, less than 1 mm of the tip affected. Could it be calcium toxicity? When I was mixing my past nutrient solution (which I have now replaced) I was playing the "chase the pH" game between gallons during the water change. The first gallon I mixed was 5.3 pH so the next one I mixed was 6.2, which I figured with the ~.5 gal at 5.4 would all average in the right range, and did. And anyway I had one last gallon to mix that I could further adjust with. When I mixed the 6.2 water though, it partly turned a cloudy white and now I seem to be reading that that is a indication of a chemical reaction that causes some sort of breakdown in the nutrient solution? So now I'm all paranoid wondering what I did to my poor plant during, of course, the flowering phase. Luckily only one of the smaller buds seems to be directly affected thus far, but I gotta believe all the damage done to the leaves is going to hurt bud growth.

Wow, that ended up being longer than I anticipated.

[the big smoke]

Any ideas?