Pollyaddict, aside from the red bringing out the markings to the max on all your polys. Have u noticed the light that reflects the red and changing the water color hues? Kind of the similar effects of those arowana 'nan' tanning lights. It makes the whole tank so vivid and nice to look at.
Only downside, of the light reflection of the red gravel for me is its too bright on my samsung s6 phone. It makes my photos and videos way too bright and have to dim it down. That's why I mixed the natural substrate in.