Spots on leaf. What deficiency?

so found these spots on some of my
Leaves but not all, what type of def is this?
Been using organic grow and bloom as well as some cal & mag it's week 8 of my cycle today and there autos but they only appear on one plant.
Don't want them to fuck up now also this is my 1st ever attempt!

Thanks in advance!

Be careful how you treat that because people might come along here and tell you its deficient in this or in that when whats really going on is it's already being overloaded with whatever bloom nute your using. I'd back off with that and just use plain water for a few feedings.

I'd run a few gallons of ph'd water through it. Those spots always emerge when there's build up.

It's watering day tomorrow so it will be throughly flushed!
Will using cold water be making any difference? As a lot of people use a bucket in the same room to let the temp stabilise but I don't have this option so I use it straight from the tap then add grow, bloom and cal/mag then water. Would this be an issue?