T5's to MH

<a href=showthread.php?s=&postid=10432247#post10432247 target=_blank>Originally posted</a> by DarG
Rich, why is that misinformation. I was under the impression that 250 watt DE 10000K and 400 watt SE 20000K was, generally speaking, close in PAR. Just checking Sanjays site, there are many examples of this using his bulbs comparions, that seem to hold true. That's 250 watt 10000K DE to 400 watt 20000K SE, not even 6500K DE. Seems that there is a slight edge in par with the SE but in general it seems pretty close.

I dont think that kau_cinta_ku was intentionally spreading misinformation. Again, there are exceptions, but generally speaking, they dont seem all that far off.

For the 250 watt DE VS SE, I was surprised because I thought you were right that the SE was usually higher. But again, checking as many of the same manufacturers equivalent color temperature bulbs in both DE and SE versions that it was about even. Some manufaturers SE versions was higher than DE versions of the same K rated bulbs. But with other manufacturers, the DE versions of the same color temp. rated bulbs had higher par.

Ahh come on, what would Sanjay know about it:D

The DE's main advantage was due to the ability to design a better reflector for them. The Lumenarc and Lumenmax reflectors have kinda leveled the playing field.
 
ty DarG, that was what i was reading to get my info. which is why i stated it. trust me i don't like to lead ppl the wrong way and want to be corrected if i am wrong. but i trust sanjay and was going by him. just couldn't find the site i was looking at to post my argument.
 
I don't mean to hijack your thread, but may I take it on a slight detour. "The Grim Reefer" uses a common physics formula for decreasing light intensity as distance from it's source increases. Intensity decreases at the square of the distance. I wonder why this is so often used in reference to aquarium lighting. Almost no one uses a point source light ( a single point of light radiating in all directions) so the formula doesn't work at all. Everyone uses reflectors of various quality and spread. This makes calculating loss from moving a light farther away from the surface without actually measuring it really hard to do! I'm not trying to start an argument, just trying to cast some "light" on the subject
 
In this case a halide lamps is very close to a point source. With a perfect parabolic reflector which doesn't exist the light decay would be linear. It would be impossible to account for numerous factors that will influence the exact number. I just point out the best you could hope for would be linear drop off. That partially explains how a set of 4 54 watt lamps can put more PAR to the sandbed of a tank than 2 250 watt metal halides. The true linear design of the fluorescent lamp and the fact they are used in an array are also important factors.
 
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