Well, yes I understand perfectly what you're getting but this is also an illusion. Let me explain why I'm being so obstinate.
🙄
In the morning the sun rises over the horizon. Think about what color the sky is at dawn....red and yellow. Well, that's the color the plants see and get colored by. As the sun rises higher in the sky the reds and yellows get filtered and the blues dominate. In fact blue is so overwhelmingly dominant during the brightest part of the day that our eyes have to filter out blue. Our brains have very poor blue sensitivity. That's why in a dark room with blue light it seems dim to us and we have difficulty with acuity in this light. Have you ever seen a video taken outdoors by a so-so videocam? Doesn't it look harsh with the colors washed out? Well that's the closest thing you'll see to neutral, and the truth is that it's far from neutral because of the massive levels of blue. Cinematically, when you see a movie, the reason the colors look so "natural" on film is that the photographers add filters to the lenses, or the film is processed remove the blue and to restore the other colors. This is part of the problem with color balance in photography.
Plants love blue because it has very high energy. In fact blue/violet light has about the highest energy levels of any frequency light that we can see. Our eyes also have very poor red sensitivity. Think about how dim a darkroom with red light seems. On the other hand our eyes have extreme green sensitivity so if a light has green in it then it will seem relatively bright to us. That's why most fluorescent light bulbs are very high in green, because it's very effective for us. An incandescent light bulb has mostly reds and yellows so they seem dimmer and less "clean" than a nice "fresh" fluorescent bulb.
When you view your world you are perceiving it through a very specialized filter called the visual cortex. This filter strongly affects your perception of the world. If you are in a room lit with incandescent bulbs the room doesn't seem yellow does it? When you are in a room lit by fluorescent bulbs it doesn't seem green at all. The brain filters these colors out for you so if you look at a white piece of paper it looks white not yellow or green even though it is being lit by those colors. Plants do not share this filter and they absorb/reflect whatever light energy is available. I have kept plants under natural daylight. In the morning they look dim and boring. At high noon the tank looks bright and washed out because of the overwhelming blue. So the idea that somehow one needs a bulb that reproduces natural sunlight is actually quite absurd because first of all no such bulb exists and secondly the spectral quality of sunlight is affected by the time of day in which the combination of atmosphere plus the the sun's position filters the light that reaches the surface of the planet. The best that can be done to simulate daylight in a bulb is to put lots of blue in it and to make sure that it overwhelms whatever yellow red and green light it produces.
Therefore there is no "natural" or "neutral" because not only does the color changes throughout the day, but your eyes deceive you as to what these colors actually looks like anyway.
What seems apparent is that you simply don't like look of the pink bulbs. That's normal, and I agree that if there are too many of them they make the tank look eerie, but this is a much more realistic approach than to concentrate on neutrality, which isn't really appropriate. To cancel out the effect of the overabundance of pink one merely has to use a bulb that has more blue and/or green tones to balance out the "look". Any so-called "daylight" bulb or bulb of high Kelvin rating will do the trick. Also interesting to note is that pink bulbs will do a better job of showing the red in red plants and fish. If there is enough of the other bulb colors this will hide the eeriness but the red component will still be there but will be masked in the overall look.
Here is an example of the a plant lit under "daylight" and blue bulbs alone.
Here is the very same plant with a pink bulb added. Although the overall look did not change dramatically the plant itself seemed to "pop" with better colors. I guess what I am trying to say in a long winded fashion is that trying to achieve neutrality in colors ought not to be the goal. The goal ought to be more about what colors you like to see in the tank. The plants don't care but the viewer will respond emotionally to the colors regardless of neutrality.
Cheers,
easy, just light your entire world with those goofy pink bulbs and your central processing unit will make pink disappear. 8) 