One very unhappy plant

[xGhostx]

Hey all, if someone could help me out I had issues with one of my three plants and could never figure it. Unfortunately she was close to harvest so I couldn’t correct the issue before so I’m trying to figure it out for my next grow.
soil- happy frog + perlite
Water was filtered and PhD to 6.5
Nutes AN micro grow bloom
It started with small rust spots and turned into what you see now

 

[Arthur]

Looks like a potassium deficiency to me. Cause is indeterminate. If you were feeding K, then I would look to an issue with pH in the pot. If the soil pH was on spot, possibly another nutrient locking it out... but... I ran for a long time. Dropped the line due to issues with pH drift. PH would crash about 2-3 weeks into flower. Medium pH would hit mid 5s. Lots of similar looking issues.

 

[xGhostx]

Thanks for the wisdom I’m planning on using a different soil for my next grow

 

[xGhostx]

What soil did you switch too