VHO Lighting.

[Mettle]

How does this manner of lighting compare to some of the others available for sw? I was looking at a fixture on J&L Aquatics:

http://www.jlaquatics.com/phpstore/store_pages/details/l-fl-hood.php?product_ID=fl-hd44110

But am not sure about the specific functions of a unit like this so any insight or links to literature to educate me would be fantastic!    Thanks!