i don't grow much in the way of phals, but that sounds interesting. got a pic? the reds on plants are from anthocyanin pigment and in most cases (phals, catts), the amount of red is associated in part with the light level. high light, high pigment (protective against the UV I think). pure alba plants that cannot make anthocyanins will not develop the red.
all that as opposed to vini paphs, where the amount of red on the leaves is often a very good indicator of flower color.