Nodes are purple, what does this mean, is it repairable, should they be trimmed?

It should recover once on track... i don't think you will need to do much other than fix consistency of your PPM. Strong LED can cause purple petioles, but what i see in diary leads me to a different suggestion. (read below) as far as trimming... at this stage i'd wait. a little stretch on lower limbs is a good thing at this point. Whether you top or LST etc. e.g. if you want only 4 top colas, top after 3rd node, remove bottom to, and LST until the 4 primary colas are all even in height... should be easy sailing from there. i only remove leaves that overlap and cause standing water on leaves and for general congestion. buds don't need light... leaves around buds need light. they just happent to also get it when ppl see the results they want to feel were caused by light hitting buds.. which don't produce nearly as much energy from photosynthesis as leaves.. significantly less. they are sex organs not solar panels... just like the don't store excess minerals (in re flushing doesn't help taste)... in genaral, "Less is more" ... have a reason to do it.. if oyu can't find one don't cut it off. So figure out your plan, then work backward from that to figure out what to cut and what not to. if you lollipop them, those initial axilary buds low on any limb are going to be cut off anywy... that's why i say a little stretch early is fine... even useful to help it catch up to same height, so apical dominance is shared across canopy. Removing that sort of trash early isn't bad. saves wasted resources, imho, but be on safe/conservative side. Can't undo pruning, lol. why are you alternating between 150-ish ppm and 1400+ ppm each week in diary? maybe, this is miscommunicating something? if so, adjust for that below. start using at roughly 750 ppm solution (t1.5EC using standard for US markets, google "electrical conductivity ppm" if not in north america.. assume CA and Mex have same source of cheap TDS probes) This will be a good starting point... perfectly find for younger plants. You maay find some want more or less, but probably within +/- 10% will keep 95-percent of plants happy. 1400-some is REALLY high. you are pushing limts of what will kill a plant (US standard EC conversion... refer to table if not in US). https://www.perfectgrower.com/knowledge/knowledge-base/ec-to-ppm-conversion-chart/ Use the guaranteed analysis lables to confirm and tabulate each molecule of importance. (manic botanix has a nutrient ppm calculator) since you are cycling with really low nutes and really high nutes, it's hard to know if it's lockout or deficiency. P-def givs the purple petioles and blueish tint to leaves. Strong LED can turn petiols purple and cause purple in stems too. i'd lean deficiency, because a hydro medium shifting ppm is an almost immediate effect. check out the ratios of nutes i use... soilless and hydro are the same in that sense. readily available in same proportions relative to any factor known/unknown that matters. i'd try to stay closer to 6pH as that gives more room for error.. you dip much below 5.8 and you are inviting problems or some esoteric mix required to mitigate influence of pH. You can go as high as 7 and probably not have much of an issue, tbh... but slightly acidic is supposed to be better. the screenshots in my diaries show lower values than what i use. When temps and RH are good, i use a low 700-some ppm mix. N can be as high as 140ppm in mature vege, but you want it near 120ppm in bloom to avoid any toxic build up, in my experience and roughly 6pH. The ratio of NPK Ca/S/Mg all can impact this... if all in a happy range, this should be a good ballpark concept to follow.