In day 40 of flower Leaves tips Turing brown, something's wrong

I am doing a fox farm soil grow. Mars led 1000 light, gorilla lite 2.5x2 tent. Gorilla glue seed from ILGM. 1st time grow. Had ph issues early, the run off was 5.0 for some reason but flushed before flowering and the plant is just shorter overall. 18-20 inches at high points. Any pointers or recommendations are appreciated. Been watching and reading a lot. Oh and ibdo fox farm nutes. The big 3 and the 3 ones for flowering, bembe, the kelp one and sledgehammer. Today is day 40 of flower planted in soil April 10th. Noticed leaves are turning brown and have some spots, can't figure it out, would love any opinions from you experts. Any questions let me know