If it is more color pop you are after than having more lights or more powerful lights will achieve this as you will be able to lower the white channel while maintaining the par at a bluer spectrum. If I remember correctly, an XR30 G4 is able to put out more par than a Hydra 52HD. In that case you could achieve a more blue spectrum while still maintaining the same par levels. But then again I would consider 2x 26HD better than 1x 52HD and they 2x26HDs will put out slightly more par than 1x52HD. You may also loose some of the "blanket" of light dropping to a single light. A better option might be to add a good quality light bar to the 26HDs and might save some coin.
If you are trying to improve the actual coral coloration than I would say work on the water parameters a little more. I saw a few months back your nitrate and phosphate ratios were somewhere around 1:10 nitrate to phosphate. Have you brought the po4 down since then? I also agree 100% with
@Mppp about keeping the levels at 1:100 is a much better ratio for home reef aquariums. I felt like I always saw peak coral coloration and health with my nutrient levels at ~5ppm nitrate and ~.05 po4.
