Need help identifying problem!

So I know there's that nutrient deficiency chart but for the life of me I don't know what this is... it's only on one strain trainwreck!!! If anybody can point me in the right direction I would really appreciate it..

Looks like Phosphorus which is commonly used during flowering. But just giving me a little picture of the leaf without any details will likely lead to you performing the wrong corrective actions. For example an excess of Calcium can push out Phosphorus and certain things can mask such as Mg deficiency which ends up being a transport problem stemming from Mg, versus a lack of Phosphorus. Or a lot of times you could just running out of root space, or watering with straight RO water or a bunch of things. The devil is always in the details.

ryanalan, unless you put up more info about your grow no one here can help you. what soil are you using? what ferts are you using, if any? what are the room temps like when light are on and off? if you're adding ferts, how much and how often do you do this?

yellow bellow and yellow burns on top. Too hot and too much water.

Too much N as well, look at the leaves that aren't yellow, they all got the claw

Also how you prepare your nutes will make a dif. Do you condition your solution first ? Your plants may have some lock out going on. Can you flush with phed water 2/3 times the pot size check the first run off for ppm first gt, then the last gt. Compare the results if no dif or little change, then it was just a watering , but if it is a big dif than it might of helped wash out excess and they will recover. But I lost some plants that looked like that because my ph meter was malfucktioning. Good luck and try the flush. Some else might disagree with me and they might be right so take all advice and be careful with it.

Ok so I'm in a 7x8 room with a 1000 watt MH 18hrs on 6hrs off, my ph is 6.5 using fox farm Ocean forest mixed with a lil happy frog.. My temps are 71-74 degrees w/ lights on. 66-68 w/ lights off.. And I'm using Canna Nutes Terra line.. I feed every water which is what I was told to do.. And I've never heard off conditioning my solution how do I do that??

Cannabis hates wet roots. You need to have well draining soil and starve them a bit. Each strain is different. Some indicas never seem to have enough food.

Well I ain't no expert, but I was told to use a bucket or jug depends on how much you need, start with RO water if you can, add your cal/mag first bubble it for 12/24 hours then add nutes bubble for 12/24 ph then use. That was the advice of a guy on here who helped me figure out my Ph swing issues. If you have time to condition longer you can add the micros wait then add the macros hmmmm or vice versa Idk, or if your in a big hurry, shorten everything up a little. Bubble it till you use it all. As I understand it the bubbling suspends everything hmmm that might be misleading, the interaction of the chemicals is the thing the cal/mag doesn't play well with the Ph down and that what caused issues for me I was using vitagrow up and down , the down made the cal/mag fall out, looked like a bunch of sand in the bucket, and made a clear slimy film. Using the dudes advice I was able to rectify the issue.
Idk what you use to Ph with but there's tons of info on this no need for me to reqoute.

Hth and sorry for long response and remember I ain't no expert.
Peace out Bare

overfert. you shouldn't need to fert much with FF and HF soils. certainly not every time anyway. maybe once every 5 waterings or less than that. the soils have fert in them already.