Did you say you have 0 readings with a Phosphate hanna test, is that 0.00? if so, I am pretty sure that is your problem, I once did that mistake of completing eliminating the Phosphates in my tank and everything lost colors right away, I now keep them between 0.03 and .12.
I believe you mentioned that you had two gfo reactors, try eliminating one or change it to a carbon reactor.
You could also turn your lights off for a couple of days to get the deeper color on your corals, it will definitely take the pale away.
Good luck!