thats PH spotting

complete a soil runoff PH test.......
with PH corrected water (6.5-6.8PH ) pour enough water in the pots so the water runs out the bottom of the pot ...test the PH of this water....

If the PH reading is out of optimum range 6.5-6.8 PH, you need to flush your plant.
Flush with PH corrected water, till in optimum PH range, 3 times the volume of the pots rule of thumb but may require more
EG: 1 gal pot = 3 gal. flush