OG Kush Auto

As i was battling to recover this plant for 2 weeks not knowing what was wrong. Everything was on point, ph/ppm, temperature, humidity etc. With the ppm i was giving at week2 & 3 is the ideal amount for this stage thinking she was hungry so I increased ppm with no luck. Then today I checked my ph pen’s reading it was off. So all this time it was the damn ph pen giving me the wrong reading. Should’ve known. Had this problem before. Im hoping she will bounce back cos she is still young. Disappointed I wasted 2 weeks of grow on this plant. Update: ph is corrected and still showing those fading leaves. Im out of ideas now. There’s nothing else to think of besides medium now. Ive never used this soiless on its own its always mixed with coco. I have a bad feeling its muddy halfway down the pot. I am going to change medium to coco, ive got nothing else to lose at this point. Wish me luck.