This is the kelvin rating I was trying to explain but looking back did a really poor job sorry.
The curved line in the middle with the numbers from 2,000 onwards is the degrees kelvin temp.
2,000 being sunrise orange
4,000 sunlight white to yellow
5,500 clear sky warm white
6,500 over cast red
9,000 clear sunlight cool blue
14,000 and beyond actinic clear sky sea light used for marine
This is just real basic as all visible light contains light from all of the spectrum to some degree and to go into how wavelengths of light are separated and absorbed by different mediums I can just understand but cant really explain fully sorry.
Simply put light from the sun starts out as full spectrum light when it passes through atmospheric cloud cover for example some of its blue wavelength is lost and the light gets skewed towards the red wavelength, there is still blue light in there as well as green but the red is dominant. when this then hits a surface blues and greens don't show up as bright and red shows up bright. All light is good for plants and can be used for photosynthesis but generally red light around the 6,500 is said to be best for plant growth with less algae growth.
Most companies recommend either white day light, or a mix of two to show up different colours in the tank, generally what they say in the gunff on the pack is not far of.
With the moonlight leds it depends on the rating on them I would take a guess they say 420 nm and not DK.
nm is a rating of invisible light 420nm is UV 650nm is infra red, the vast majority of algae cant use this light, the only ones I know of are the marine algae that grow in coral and are need for healthy coral growth.
I have never kept reef tanks so sorry if this is not quite right.
Sorry if this is a bit heavy and hope it helps,
ady