You need to add piks in these situations, otherwise all you can receive is guesswork.

you need to tell us how big is pot6...what type soil...ph of runoff or solution. strength of nutes, etc...

Curling leafs with spots is due to either a deficiency or nute lock. Using 1/2 strength mix makes it unlikely that you over-ferted the plant; So I would guess that you have a nutrient lock due to ph that is way off.