It is interesting if plants use reds so much, wouldn't a Corallife Colormax bulb be the best? Yet ive heard people say the colormax's don't bring as much growth as a giesseman midday?
I don't exactly know. I am learning about these things as we speak.
But here's a guess - the photosynthesis is best if the blue is more than the red:
And look at the Colormax bulb spectrum:
Now look at the Giesmann Midday spectrum:
What I see is that the Colormax has much more reds and the Midday doesn't really have reds. The Midday looks like a Colormax minus the reds! Nice. And strange.
So my take on this is pretty simple. The Midday is a T5HO (an 24" bulb is 24 watts). The Colormax is 17 watts for a 24" length. S there is a difference in the intensity. In addition the T5HO are commonly used with individual reflectors. They increase GREATLY the intensity of the light hitting the bottom. So comparing Colorormax which seems to have a fuller spectrum that the Midday may be a question of comparing intensities too.
I wrote the above because recently I got a 30W LED Flood light, 10,000K, with a single EpiStar LED. The LED light color is too white. I use it in conjunction with a 24W Giesemann Midday. Got shocking pearling minutes after turning the LED on. What is interesting is that leaving only the LED leads to reduction of the pearling by about 25-30%. Leaving only the Midday on stops all pearling. It seems that the two lights somehow complement each other and the LED provides the intensity, while the Giesemann provides a better spectrum. Now note that in my LED+Midday setup there aren't many reds. I wonder what would happen if I add reds.
Look at post #16 in this thread for pictures, day by day, with the LED+Midday:
Today, on day 10 of running the LED+Midday and the plants are now making pale leaves because I do not fertilize the water yet. But they still pearl. Last night I also noticed a brand new plant emerging from the gravel - something that had been there waiting for better times. So here I have a tank with lots of light and little reds in the spectrum. But the plants don't mind it. Maybe that's why the fame of the Midday bulb lives on - it is not that it is the best spectrum but it is bright enough and normally used with reflectors that make it blast the water with even more light.