Surface water movement and Lighting

[Pete_the_Puma]

Hello,

I have this theoretical question/idea and was wondering if anyone had any thoughts about this.

Tanks with a strong water movement on the surface have much more light dispersion versus tanks with a relatively smooth Air/water interface.

So the tanks with little wavelets on the surface have more light dispersion, which I would guess is a good thing as it softens the light penetration causing more dispersion. I guess that could explain why for example some people I talk to say they run their LEDs at 100% with no problems and great color/growth whereas other people say you would be crazy to run them at 100% because they "burned" their corals at 40%...

I was wondering is this was something anyone else frequently thought about, for what it's worth I have 2 Gyres XF150's at opposite ends of the tank on pulse mode with different frequency wavelengths and the surface of the water is almost never flat, I am ramping up my LEDS slowly to 100%.


Just trying to start a discussion about this as it seems to not be a factor anyone discusses when talking about lighting for their SPS tanks.


Pete

[Pete_the_Puma]

Well i found this good article about this:

"Underwater Lighting conditions"
by Andrew Trevor-Jones


but unfortunately this is all he says about this:

"Effects of the Air-Water Interface

When light hits the water surface, some light penetrates, but some light is reflected. The amount of light that is reflected is greater when the angle between the light rays and the water surface is small. When light is coming from a point source, such as the Sun, the percentage of reflectance can be determined using Fresnel's law (Weinberg, 1976). Figure 10 shows the theoretical reflection of sunlight based on the elevation of the Sun. However, Fresnel's law assumes an optically flat water surface which would be rare for the ocean surface, and so actual reflectance may be greater. Figure 10 also includes measured values of reflectance for both smooth and rough water surfaces."

[Pete_the_Puma]

Think I should move this to either the lighting forum or the advanced discussion...

[moatdaddy]

Concur. And how is the snow. I left fort drum for Florida. Side note people with good top water movement and LEDs still have directional growth. Why I ditched them for t5

[sjfishguy]

Yes, I agree and is one of the reason I like lots of surface movement for point light sources like leds and halides. you get better light spread on average over time.