Nute Deficiencies or .............?

[Help_Needed]

I've been discussing this with a couple of growers in my grow log, as well as on another message board. I'm not confident that we've got the problem nailed down yet, so I'm looking for additional input. It's possible that what I'm seeing is the normal self-cannibalization that you see in some plants during late flower, but I think it's more likely that I've got yet another nute problem. Any help is always appreciated.

Grow Details -
DWC Drip Feed Hydro system
Lucas Formula - GH based nutes - flowering profile - 750ppm
pH - 5.6 and stable
6 - 42w "soft-white" CFL's over each plant; 2 - 26w "soft-white" CFL's in front
Room Temp - 77 average; 80 high; 72 low
Res Temps - 74

I'm in the home stretch as far as flowering goes. Based on the breeder's timelines I *should* be harvesting in 1-2 weeks. I know that it's somewhat common for a plant to self-cannibalize during the last couple of weeks of flowering, but what I'm seeing seems a bit extreme.

Depending on where I look, my plants are showing symptoms of phosphorus, potassium, and calcium deficiencies. Some of the damage is left over from when I had my heat problems a couple of weeks ago but some of it - especially the potassium deficiency - is new.

Heat shouldn't be an issue. The room is staying in the 70's (72-79) and the reservoir temp is 73.

pH stays between 5.6 and 5.8.

I've checked for root rot. The roots look good. No bugs or visible mold/fungus.

The only thing that's changed is that, based on the advice of a couple of growers, I've backed the nute strength down to 800ppm, instead of 950ppm. And because I got a bit busy this weekend, it actually fell to 750ppm before I topped it off last night.

Is this normal for late flowering?

Should I increase the nute strength?

Also, I know with soil grows it's pretty common to flush during the last couple of weeks and give the plants no nutes, and I've heard of some hydro growers doing the same. Lucas recommends against flushing when using his formula. So, flush, or no flush?

P.S. On the plus side, the buds are starting to really swell up nicely and a lot of trichs are forming, even on some of the fan leaves. I looked last night with a magnifying lense and it looks like about 30% of the trichs are cloudy. So at least from a budding perspective, things seem to be going well.

[Ganja Guerrilla]

Should I increase the nute strength?

I wouldnt change anything, this is a bad time to screw things up, youve seen other grows get screwed the last 3 weeks here on the board

Although its agaisnt the advice to flush the last 2 weeks I would flush the last week to see whats the outcome, that way there is no real risk