Why not HPS over MH???

Just wondering why you dont see HPS fixtures over reefs?
I know in Horticulture the HPS spanks the MH on all fields

 

the hps produces more wattage than lumens(uses more power than it gives light) which also means more heat.mh are used mostly because of the lumens per wattage....which means you pay less for more light!

 

http://www.topbulb.com/find/hid.asp

These arnt aquaria bulbs but the HPS bulbs have a higher lumen per watt than any of the MH bulbs Maybe its because the color temps but i dont think so

A horticulture friend said that the HPS will also have a higher PAR value than the MH. He thought the reason why aquariums dont use HPS might have to do with the light passing through the water?

Thank you for any responces
Ricky

 

HPS will grow algae faster than you can get it out of the tank
With a reef tank you are trying to create conditions as close as possible to what the corals are used to in their natural environment. Something else that is important to us aquariust's is a color that is pleasing to the eyes
A HPS High pressure sodium light is an extremely yellowish light. (comes from the sodium) It has a very low kelvin rating 2200k or somewhere around there and is undesirable for corals that are used to wavelengths of light around the 420nm - 450 nm range and a color temperature of around 10000k to 20000k depending upon the depth the corals natural habitat is.(Most in the 10 to 60 footrange.) In summary, 1.) Not great for corals who need light for photosynthetic zooxanthellae 2.) Doesn't look good to our eyes or make corals flouress

Jim