did you flush? if so are the pots still saturated, mabey theri suffocating? but if you flusehd and your runoff is at 6.0 or close then andd some calmg to your nutes, the spots look like a calcium magnesium type of defficency and lately it has been ahppening alot for soil growers. I dont know why but mabey the soil is out of some nutes?