Hi @ MintyFresh
Have a Google for "PAR vs PUR" and I think this might help answer some of your questions. Here's a good starting point:
Plants mostly reflect green light, that's why they look, err.... green!
You could have the brightest green light shining down on your plants and they would look very green, but they're not really going to grow. They need red and blue light, which is why you see some hydroponic grow lights having just red and blue LEDS (they typically look pink or purple), the logic being that green light is just wasted on the plants, so use the electricity to give the plants the blue and/or red light they need. Flowering and fruiting plants need more red light, for foliage growth (leafy veg for example) they need more blue.
But an aquarium lit with only red and/or blue light would look ghastly! In my hydroponics I use warm white "full spectrum" grow lights with some extra red and blue boosts because I want to be able to see in the same room to see if the plants are healthy etc. Ok the green light is wasted on the plants, but not on my eye's viewing the plants.
Exact same logic for tanks. All these colour tuning options are there because they can be with LED tech, not because they actually need to be! Find a light "colour" that makes your tank look the way you want it to during the day. Some mix of cool and warm white LEDs to get the morning, midday, afternoon feeling you want. Add in some extra red if you have red plants or fish and want to make them really pop out, but remember this is only for your benefit really - it won't make much difference to the plants or fish. White light (warm or cold) has everything the plants need to grow and for you to look at them.
A dim blue "moon" light for an hour or two of an evening is not going to make any difference to any sort of plant (or algae) growth.
These options are really only there for you to play with and enjoy (some might say gimmickry). They will make very little difference to the tank life. If you get algae, it's almost certainly not because of an hour or two of blue dim moonlight each night!
I short, set the light colour to whatever you like the look of. It's the intensity that will make the difference to the plant life, not the colour.
Hope this helps, regards, James