Durban Poison Auto

It might be a calcium deficiency but the spots aren't usually like that and the tips are usually burnt. Take a couple more pics and add if it appears on every leaf or not bedause it might be the development of fungus. This might be the case if you water on your leaves rather than directly in the soil

Normally happens to me, if the plants get to much light.

Phosphorus Deficiency because the spot looks a little blue or red check the soil PH to be sure if PH is good.. Then is calcium