Ok I just re read the posts here and I see what caused all this .. I assumed that beacuse a miror was wanted that were were talking about flat reflectors only (my mistake) yes if you can go with a parabolic then that is the best but my opinion was on using a flat reflector on top of your light, and in "My Opinion" I would rather have a reflector that difuesed a point sourse light than a spectral reflector in this instance. the reason for this is if you have hot spots you get burnt plants maybe this is not as important in a reef but, I have been playing with planted freshwater tanks for about 22 years and making my own lights for the last 16.
a good article to read with actual studies on different reflector material is by
RICHARD HARKER
another statment by Tom Miller
"Glossy white reflectors are also quite effective. A very glossy enameled white reflector can come very close to the same reflectivity of a good mirrored reflector - such as polished and anodized aluminum. Flat white reflectors are less reflective than glossy white reflectors. Non-mirrored aluminum reflectors likewise are not as reflective as highly polished mirrored aluminum. Aluminum is very reflective when polished and protected from corrosion. Aluminum is a very common, less expensive, and high reflectivity coating used on many astronomical telescope mirrors as well."
so I apolagize for any wrong info that might have been derived from my post.
Steve