Problem with leaves

This purple coloring is from a substance called Anthocyanin. It is harmless and is produced by the plant itself when it needs to protect itself a little from environmental factors such as strong sun or cold nights. Most cannabis plants produce anthocyanin near the end of their lives regardless - - especially when subject to cold-ish temperatures - - and as such is not a sign of anything else but age in your case.

hey there, the colorful splotches are actually a potassium sign , i guess this beast is just really hungry for K which is very much used in flower and resin production. Looks like it's quite late in the game, so i dont really recommend changing anything, just proceed with you flush and enjoy the colors. Hope this helps ! 🚀