I just learned about this product and was wondering if you were aware of it and if you had considered it for replacing some or all of the M/H in your tank ? (at least part of the time when the outside light is sufficient)
It seems to be a bit expensive but since cost is not a decision breaker in this build...
It would seem to me that natural sunlight, if it could be brought conveniently to your basement, could probably qualify for a best practice for growing corals
The spectrum seems a bit lacking over 600nm (
http://huvco.com/content/parans/LightSpectrumChart.pdf )but it might not be such a big problem since if I interpret the chart on the 3rd page of this link correctly (
https://qir.kyushu-u.ac.jp/dspace/bi...0004506687.pdf ) it would reflect the spectrum at a depth of 5 to 10m pretty accurately. It would also be supplemented by other lights anyway.
Appart from the savings on electricity, you would also get a much more natural-looking sunrise/sunset since the color of the light changes during the day (would probably work well for moonlight too, and who knows maybe even start your corals spawning
).
"
The HUVCO – Parans Fiber Optic Skylight is a unique way to bring natural light deep into an interior space. The system is comprised of an exterior daylight collecting panel which has 64 Fresnel lenses on the inside. These lenses rotate to track the sun automatically, controlled by an internal computer. Each lens acts like a magnifying lens to focus the sunlight. This focused sunlight is directed into a fiber optic strand, each individual strand is combined with other strands to create a fiber optic cable, 6 mm in diameter. There are four fiber optic cables coming out of each panel. Each of these cables can be up to 60 feet long.
These cables can be routed through walls or ceilings and bent around obstructions. Each fiber optic cable can be used to bring the natural light to a different interior luminaries; or they can be combined in one luminaries. There are a variety of luminaries available, some of which combine the natural light and electric light into a hybrid fixture.
The hybrid fixture can be combined with a sensor that will automatically turn the electric lights off when the natural light is sufficient"
http://huvco.com/products.php?product=parans