I went through the same issue you're having...not knowing that my lack of nutrients were causing the SPS to bleach/look pale. I've been dosing phosphates/nitrates regularly, and everything has colored back up and looks great.
Stop running phosgaurd and trim back your macroalgae. Not sure how big your tank is and how many fish you have...but if you have a heavy bio-load...you can try overfeeding to see if that naturally brings your nutrients back up. If not, just dose.
I use Swanson monosodium phosphate and Spectracide stump remover (nitrates).
I aim for .04ppm phosphates and 5ppm nitrates.