Please look at the last picture , i think its N de...

Just go 50/50 veg bloom nuts and see if it improves

First thing would be cal-mag

Your colas look very good.
Week8 -fan leaves colors/discoloration/dying is irrelevant. As long as colas fattening amd healthy .
Plant is doing last efforts to reproduce by taking all minerals for the buds and not for leaves /growing.
Looks great-i wouldnt furt anymore.just ph water

Looks to me like too much water and it’s drowning the roots. The leaves while pale are also heavy and hanging. They also look puffy with speed bumps on the leaf surface

I would not be too worried about that older leaf yellowing. Indeed, at week 3 of flowering I starting taking off fan leaves that are not 100%. Those that are 100% healthy but shading bud sites below, I tie out of the way.

I've found that doing this defoliation at this time helps the plant if it is going through at Nitrogen deficiency, because there are less leafs for her to fix if I've removed the <100% ones (and she does not have to waste energy/resources trying to fix those <100% leafs).

Make sure your ph is 6.1-6.4 now as you want it to be slightly higher than in veg (5.8-6.2) imv. Check your ph out from your run off as well and water/flush until it is within 0.1 of what goes in. Check your ppm's out if you can as well and post them numbers.

HTH! :)

Hi there! I'm thinking about a PH issue in the past weeks that results today in a Manganese deficiency. I've never experienced such symptoms at this stage whereas I'm also using BioBizz nutrients, and I usually stop Nitrogen (BioGrow) intakes just after the stretch peak, so around 12-15 days before you. Plus, your leave's tips are already burnt, that makes me think you overfed them in the past. As an emergency move, I would flush the soil with plain PH'd water for 2-3 days water before going back to giving regular doses of blooming/flowering nutrients. I'll be around, keep us up-to-date so we can help you to adjust any parameter if necessary, and good luck!

Though I've seen strains that need 2ml/lt of Biogrow on the stretch phase, you are using a 18 liter pot and going from dark green leaves, almost N toxicity, to N deficiency in 2 weeks is doubtful, specially since the rest of the foliage still is really dark green and that amount of soil should feed the stretch phase without the need of aditional nutrients. Two weeks ago you posted a picture where there was a strange yellow spoting too. Check your pH before doing anything, it's most probably the root off your issue.

BioBizz nutes are supposed to be pretty amazing. This looks like it could be a PH issue more than N. I don't see you mentioning PH in your diary. Have you been checking PH?