it LOOKS like you are using a 21 emitter array. The 15k looks like it has about (guestimating based on spectra) 5x white (yellow phosphor), 10x 465, 4x 455 and 2x 406 nm emitters. If I had a free hand with the reef arrays, I would swap out one of your 465 and one of your 455 nm emitters and add in an additional 406 nm and then one of your 675 emitters. This would help give both better fluorescing, and handle the reds much better then what typical arrays use over reefs. You don't need a lot of red, but the broad band yellow phosphors really do not do (imo) justice to red pigmentation.
only estimating the wavelengths given what bandgaps are available and what it seems like you have access to