Hi I’m new at growing. I am growing in coco coir 70/30 perlite mix with a charge added in. I planted cbd crack auto flower and it started off excellent. But as time has gone on it’s starting to show burnt tips and the leaves are clawing under. The only nutes I use Is canna a and b along with cal mag. Also it’s grown under a led light. It’s 3 weeks in and starting to flower on top and it’s only about 6 inches tall. I flushed it yesterday hoping to correct whatever problem that has posed itself. The approximate grow time is about 75 days for this strain. The ph is 6.5. Any help or suggestions would be great.