1 of 4 Plants in DWC Showing Real Heavy N Deficiency?

I have a 4 site dwc, 4 different strains.

~900PPM / 6.0PH / GH Full Line

One strain, the biggest one has heavy yellowing this past week. Looks like tell tale nitrogen deficiency. I also have some leaves going brown, crispy, and falling off (like tree in the fall/winter months).

I'm not sure what to do since the other 3 girls look nice and happy (they have some minor phosphorous deficient leaves at the real lowest part of the canopy with no light.). Should I bump up the nutrients to 1000-1150?

About week 6 of flower, so flushing should start soon. But this 1 girl already looks like I've been flushing her!

Yes

You're in late flower. Dont you want less nitrogen?

Looks more like a severe sulfur/mg deficiency and you want lots of that at the end of flower to promote resin growth.

I'd just dose with some Epsom salts this close to the end.