Spotting a problem?

I'm posting this as a helpful thing for new growers hopefully.
The spot on this leaf and burnt leaf tip are the only things marring 100% green growth. The spot is a burn from adding fertilizer. It's a sign to back off with a sensitive cultivar. Also conversely...the plant is rapidly growing...it is using nutes quickly and fertilizing can make rapid growth that shows as deficiencies in the fan leaves. That's okay if your flowers are healthy and the deficiencies are from the plants natural cycle.

I think the high EC inhibits potassium uptake which causes the spot/burn. Potassium regulates the leaf surface temperature.
The concept of reverse plasmolysis is one every grower should know. If the salt content of your media gets too high, your plant will lose turgor pressure and instead of the plant taking water from the soil, the soil will suck water from the plant. Causing all that ugly necrosis.