HELP! Yellow Tips and Yellowing of Leaves

[Tone22]

Hi All. Hope all is well with everyone. Growing a Stardawg, noticed some yellowing tips a few days ago, which has progressed and some leaves going patchy yellow. Pics of worst attached. Also seen purple stems. Day temp 78-80, night 70-75, 40-50% humidity, soil PH spot on 7. 5 weeks into flower. Been feeding Canna Terra Flores twice a week and low dose of Cal Mag every week or two. Gave her a good flush at 70% of the normal feed today just in case. Any thoughts would be gratefully received. Thanks. Take care.

[dilvish]

PH at 7 is a bit high for soil...should be around 6.5. Hard to tell without looking at the whole plant but it could be nitrogen toxicity judging by the color of the leaves...they look very dark green.
At 5 weeks into flower I'd say just give them properly PH'd water and let them go...they should almost be ready but again we'd need to see pics of the whole plant

[Tone22]

Thanks, good advice. She's looking happier now.  Probably only two weeks from finishing, some pistils are turning orange.