Hey gang,

A new Sanjay based report is out this month..

Analyzing Reflectors: Part II - Double Ended Lamp Reflectors


Interesting/cool, as this is good info since I'm about to go to 250w DE bulbs (PFO, & AB bulb) for those of you I've talked about this..

An interesting comparison is the one between 250W DE systems and the 400W lamps reflector systems. Since both used 10000K lamps (although from different manufactures, and of different styles), we could try to determine whether we can replace 400W systems with 250W DE lighting system. This would be economically quite beneficial to the aquarist, in terms of savings in power and minimizing heat additions to the tank. Interestingly when comparing the total incident light over the 3X3, 2X2 and 1X1 areas there is only a slight decrease in total incident light, while the lamp power is decreased by 37%. Why is there such a disproportionate difference? One possible explanation could be that the 400W fixtures are not as efficient as the 250W DE fixtures the small size of the DE lamp allows for better reflector design and allows more of the light to get out of the reflector. With the 400W systems, the larger size of the lamp envelope may be causing some of the light to reflect back into the lamp envelope. Another possible explanation may be that the metric being used (sum of the total light at all the measured points in the specified region) is not capturing this correctly. A better metric may be the integration of the volume under the surface in the intensity distribution graphs. This aspect of the comparison needs to be analyzed further since it has significant practical implications. For now we can make this comparison by visually analyzing the graphs showing the light intensity and distribution.