
.... lights are OK for intensity and distance... I get the dilemma with T and lights. I use a small space heater in my tent when it's running because it's in an outside courtyard. Keeping the lowest T over 65F+ is a big help to the plant's uptake and metabolism...
So, after more than a week of elevated ppm's and she's actually getting worse, with multiple defc. symptoms still, I can only conclude something is screwed with the damn coco... Best bet is some sort of antagonistic uptake issue, and/or pH in-pot, not the soln. going in,... This is the down side to bottom feed pots in coco =

... We are blind to these two very important factors, pH and ppm load in-pot,... More remotely in likelihood is a root problem, not to say both can't be in play... The snag with MC is you can't elevate parts of the feeds to deal with things like micronutes defc. (and this is still looking like B defc to me) without adding in more of what you don't want.
....purple petioles isn't a good diagnostic clue because many strains have this as normal expression, but purple striping on the stem is a clue to overall nute defc., which we suspected early on here,...
Lowers I can't see, but likely it's N, maybe Mg defc.... N is normal up to a point as you know, but if it's Mg, it's not because of lack at this point! Again, back to antagonistic uptake issues,..
Only thing I can think to do mate is to pull the pot off the res', and do a coco-style flush... more feeds haven't helped, and my best guess at this point is a cumulative imbalanced salt build-up in this pot... I can't be sure if the coco's CEC buffering with Ca/Mg is off either, but it's suspect...
...flush soln. recommendation I saw was with RO/Di water + 150ppm Ca-Mg, + 150ppm nutes, pH 6.0; pour through until inputs are at or near run-off values...
With your 77ppm water (nice!) you can use that, go 200ppm total tap + Ca-Mg, but keep nutes at 150 initially... The idea here is to test that initial flush r-o for ppm and pH to see if we are on the right track with this, purge excess if that's the case, and see if the Ca CEC buffering and be "rebooted",... give her a day, then hand feed at the usual ppm's to restore what's been stripped out of there ASAP, and same for the res'....
You can speed up further draining by placing the pot on top of some newspaper and a paper towel or two that has direct contact with the drain holes to facilitate capillary action.... This pull more air into the coco too!
This is frustrating, I know, I'm pissed too...