I just don't want to go down the wrong path on my next decision 
... but the upper and mid pics show more classic P defc. symptoms, broad patches of necrotic tissue,... not that you can't have both at the same time! And with coco's high CEC demands for Ca, it's a common issue to have,.. what's your feeds and Ca-Mg supplementing? Or are you using coco-specific nutes which deal with extra Ca demands? And do you have any idea what the in-pot pH is? Coco is a rather specialized medium, with unusual CEC properties, and cannot be treated like regular soil, or troubles will come! pH for coco is best high 5' to low 6's, from what I've seen reported by our coco-nuts,... Too much perlite as well, BTW, unless you're running it close to full -on hydro style? Coco has great breathing on it's own, so lots of perlite isn't necessary,...
:smoking: Hey Clix-- purple peti's are common enough from genetics and strong light responses, so this isn't a solid diagnostic clue by itself, but it can help confirm,... If you check out the Defc. Pic Depot here It's ion the top section, the Sticky's) and look up Ca and P defc., you will indeed see some symptom similarities-
Check the pH in there to confirm if it's off, which may cause lockout defcs.,... hopefully it's just a lack-of issue, so simply upping your P and Ca-Mg will resolve this,... if it's off, adding more nute's will worsen things and needs to be flushed,...
I am using coco specific nutes the ph of the coco is around 5.4 to 5.6 Im using a color test that's why not an exact number and my nute solution is around 5.7 to 5.9. Its good to know about the to much perlite thing. I am treating like hydro slowly building up to multiple waterings a day but I may have not up it fast enough. My ph in the medium is low compared to what I like but once coco pics its ph its almost impossible to change its mind. I've tried on multiple occasions to do so. All that happened was it moved up one point and went back the next day after using gallons of water to try and change it lol. I will double check all my numbers tonight when lights on just to be sure before I make any decision on adding more food. I used to have a digital ph pen but I broke it. While I had it though I was able to use it to verify what my color tests would says and what color meant what ph. So at least I have that going for me for now lol. It was actually the Pic depot that got me lol I origionally thought Cal/Mag but then checked the guide here and was like ummmmmmmmmm hmmmmmmm lol
glad to help mate! ..look up Waximus' DIY drip system for coco, a fine set-up for sure, tried and true... plus Waxi is a true gent' and will always help with things! I myself have yet to try coco properly, and when I do, it'll likely be with an Autopot set-up (oh yeah-- duh! ), something else you should check out for sure! Hansbricks is our Guru there, he gets amazing results from very little effort,... 
Deal
.. try to get your pH up to 6.0 at least for coco, you're getting too low and edging on defc. level pH... keep in mind, the roots actively create some acidity from the nutrient uptake process,... what's you water source? Is it RO or DI? They has no pH buffering minerals in it, and the nute's alone (if they have some buffering capacity) can't pull all the weight on this,... using an all carbonate based Ca-Mg, like general organics CaMg+ can help, as will some harder water... it may be why the pH is so stubborn about raising.... Bro, get yourself equipped right, you need these for coco and even soil: a good pH meter (for liquids), a TDS or EC meter, and for in-medium pH readings, an Accurate 8 pH probe...
And will do Waira I am on that shit like cookie monster on cookies 
I like your idea of an all carbonate add in that shiz raises ph like a mofo. I totally forgot about that and by chance I have some GH calmag +. Always a pleasure friend Oh ya and yes I am using Distilled water
Ahhh, that explains some things,... DI isn't bad at all, you just have to compensate for the utter lack of buffering minerals that usually would be in the water,... And yup, this type water is susceptible to wild pH swings from small inputs and instability because of that lacking,...that's why your pH shot way the hell up from the CaMg+!
