Failed Grow, what went wrong?

Hey riu community,
I am currently doing a speaker box grow with a kryptonite and a chemdawg 4 in a box that's about 13 inches wide by 9 inches deep by 24 inches tall. I started out using 3 23 watt cfls in the box, but about half way through flowering (ie. like 2-3 weeks ago) they both started turning brown at the top buds, the leaves started from the tips and the brown crunchiness moved in towards the buds, the white hairs have pretty much turned all the way amber/brown on the top buds. I originally had thought it was nute burn (I'm using Tiger Bloom, but don't have the tools to measure it accurately so I was kinda guessing (I know, a bad practice) so I quit giving them nutes, and they got worse, so now my best guess is a phosphorus deficiency that was originally because I wasn't nuting them enough, so I gave them a larger amount today then I usually do. I also have a negative ion generator going in my room to cut down on the smell (housemates don't know about it) and I had it cranked way up because I didn't think it would hurt anything (coverage for 2000 sq ft, my room is like 150 sf) and I'm wondering if that's what made them dry out so much at the top. I've been watering when the soil feels dry till about the second knuckle on my finger which works out to be like every 3 days. What do you guys think happened? I'll put up pictures when I can. I've decided at this point to chop all the top burnt buds in a few days and just make them into some brownies, at least it won't go to waste.
Thanks,
gdoggrower
 
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