Iron is not mobile within the plant, and so iron deficiency shows up as pale white new growth. Old growth remains healthy. New white growth is normal size. Re-greening and new growth in plant (on right side) 4 days after iron addition.

Pale new growth without old leaf deterioration is characteristic of iron deficiency. These are jdmstop's photos.

Iron deficiency is characterized by whitening of the new growth. In severe iron deficiency new growth will eventually show signs of deterioration and develop clear areas and then large holes. No old leaf deterioration.

Pale/transparent new growth shows a severe iron deficiency.

This is iron deficiency. Iron deficiency is characterized by yellowing of new growth first, then old growth sometimes follows.

Notice the 1/2 white 1/2 orange leaf. That change occured when I started adding trace to the water. Iron deficiency in middle and older leaves, iron added and plant recovered.