the question is does the new growth darken up as it ages? if it does, it's not a big problem, if it stays that light as it ages thats definitely a deficiency of some kind, more than likely iron, but it's hard to say from the pics you posted. iron deficiency is usually caused by high soil ph, which is easier to rectify than most people make it out to be. IF that's what it turns out to be, just drop the ph of your water by about half a point, water till you get good run off, then wait and see what happens in a week or so.
do not expect your soil ph to be constant, it never is, but it should be in a certain range, somewhere close to 6.0. it rises and falls as you add nutrients and the plant uses them up, but it should be staying between 5.5 and 6.5 all the time. if it's consistently high or low, you need to adjust your feed accordingly to bring it back into that range
