Phosphorus deficiency?

[Bookush34]

just seen this today. Have a few tops doing this. So far only on my GG4. The Cali OG Kush looks fine.

Never grown GG4. But it’s only week 5 of flower. Think it’s a little early to be turning colours.

 

[Capn-Crunch]

P&K will both show in flower. How much P&K are they getting?
Also some of the leaves look quite pale?

 

[Bookush34]

I am feeding
RO water 0ppm
Tap(well) 50ppm
Cal-mg 100ppm
flora nova bloom 500ppm
Koolbloom 1ml/L
Flora nectar .5ml/L

Ph 5.8
100% Perlite Hempy

 

[Capn-Crunch]

I don't know the PK ratio of those nutes, you should try to figure that out though

 

[Bookush34]

Nova bloom. 4-8-7
Koolbloom 0-10-10
Flora nectar. 0-0-1
Cal-mg 2-0-0

 

[Capn-Crunch]

Nova bloom. 4-8-7
Koolbloom 0-10-10
Flora nectar. 0-0-1
Cal-mg 2-0-0

Those numbers look very low to me in K, and fairly low in P.
As I said before some leaves look faded as well, but if your other plants look fine it could just be a pheno specific issue.
I normally use a ratio somewhere in the 14-30-20 range in flower, but that's on fairly large outside plants.