This is my first grow and I am using Autoflower Northern Lights in a coco/perlite 60/40 mix with Fox Farm nutrients per there recommended schedule. I am nearing the end of week 9 and one plant is nearing maturity faster. The last two weeks I fed Fox Farms Grow Big, Big Bloom, and Tiger Bloom at 1400 ppm total. On Tuesday of this week I noticed some light nutrient burn and some brown spots on my fan leaves. I tested my runoff and found it to be 4000 ppm. I did a flush with Sledgehammer and have fed 6.0 ph water only since. My question is can I get another two weeks out of this plant or should I harvest now. If I continue what should I do for feed