Dark spots and yellowing: Need Help Diagnosing

This is the second grow in a row I have encountered this issue of dark spots and yellowing towards the end of flowering. It happens in the last few weeks and only gets worse until harvest. Need help diagnosing so as to avoid this in the future. Plants got a slight note burn last week, but from what I've read so far this seems like a deficiency. Have had the same issue using Floraseries as well.

Week 6 of Flowering
Nirvana AK48 feminized
Hydroponic GH Waterfarm buckets with clay media
Pure Blend Pro Bloom
CalMag+
Liquid Karma
BioBizz Topmax Bloom Enhancer
Hydroguard
RO water
pH runs between 5.9 and 6.3

Its most likely genetic

Blurry Face said:

This is the second grow in a row I have encountered this issue of dark spots and yellowing towards the end of flowering. It happens in the last few weeks and only gets worse until harvest. Need help diagnosing so as to avoid this in the future. Plants got a slight note burn last week, but from what I've read so far this seems like a deficiency. Have had the same issue using Floraseries as well.

Week 6 of Flowering
Nirvana AK48 feminized
Hydroponic GH Waterfarm buckets with clay media
Pure Blend Pro Bloom
CalMag+
Liquid Karma
BioBizz Topmax Bloom Enhancer
Hydroguard
RO water
pH runs between 5.9 and 6.3

View attachment 3557508 View attachment 3557509

Click to expand...

Are they drinking less water then before?

Blurry Face said:

This is the second grow in a row I have encountered this issue of dark spots and yellowing towards the end of flowering. It happens in the last few weeks and only gets worse until harvest.

Click to expand...

Looks like salt buildup to me. If you have a ppm meter measure your runoff ppms. That always informs me if I'm getting buildup. It's common if you're not watering for 20-30% runoff and/or feeding too strong.

You killing it with all these additives, all it needs is a full dose of main NPK bloom and half dose of cal mag, PK boost only needed on the 3rd week before harvest and on until week 1 before harvest. Then just feed water only, let bitches cannibalize themselves )))

Could be a Calcium deficiency due to your ph range. Top end of Ca absorption is 5.8 area (hydro) and bottom end 6.5 (soil). Seems like there are plenty of nutes, so this would be my best guess. What medium are you using? If you are using soil, try a slightly higher ph, and if hydro, slightly lower ph. Also, do a google search for Calcium def and see if those images match what you have going on.