Please help identify what is problem here

Please identify what the heck is wrong with my plants...is it Nuteburn or is it a calcium deficiency or a potassium deficiency or maybe leave septoria....what is it please.
It's Durban Poison outdoor growth in 3 gallon pots. Feeding on Seagrow organic fish emulsium since starting grow 3 months ago. All was fine until I had what I thought was thrips and used a once off fiolar spray of spinosad. Then 3 days later this problem started. I thought it looks like potassium deficiency so I added some hardwood ash (1and a half teaspoon in 1 liter water) for each 3 gallon plant. That was 2 days ago. Problem still not solved.

Septoria often starts on the lower leaves in early flower, you must be in the start of early flower growing in South Africa. Are those spots on lower leaves? If so it looks like Septoria. Im no expert but I would remove those damaged leaves. Hopefully someone who has had to deal with Septoria can jump in with some info.