Yellowing of leaf tissue w/ the leaf vein remaining green- Fe chlorosis.

You may be using a nute w/ insufficient Fe, but I think it's more likely the lower availability of Fe @ higher pH. Try dropping it down to 6.0- 5.8.

Foliar feed w/ a good micronute @ about pH 5.5 should clear it up quickly.

Best I can do- can you get a pic in focus?

Brown/yellow spotting likely a Ca issue- again, try dropping yer pH.