Not everyone runs MH and not all MH, at say 400 W, necessarily produce the same amount of
light. As I said, you must of missed it.


EFFICACY = Lumens / Watts

All one has to due is look at any 400 W MH and compare it to 400W Iwasaki. No MH @ 400 W
even comes close to this bulbs light output.


"then you would say "It doesn't matter".

I never said it does not matter. Do not be putting words in my mouth :-) It is misleading.
I said "A 400 W lamp or 40 W lamp says nothing about how much light it puts out of any
kind". . Almost any 175 W MH will _usually_ but _not always _will have more light output
than say a 150 MH


Boomer

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"Wayne Sallee" wrote in message
ink.net...
: But if watage says nothing about how much light it puts
: out, then when ever you order a mh light system, and you
: are asked what wattage you want, then you would say "It
: doesn't matter".
:
: Wayne Sallee
:
:
: Boomer wrote:
: A 400 W lamp or 40 W lamp says nothing about how much light it puts out of any kind.
Most
: lamps use this wattage to drive themselves. On the avg about 75% of the wattage is for
: driving it the other 2%% will be actual light output Some of the more hi-tech stuff
drives
: more light output, as it use less wattage to drive it.A simple way to look at it is to
: look at the wattage and the lumen output. A 100 W bulb that has an output of 10,000
lumens
: ( say a MH) has an EFFICACY of 100 ( 10,000 / 100). A std incandescent. only has an
: output of about 10 lumens / W, so you would need a 1,000 W lamp to be equal 100W MH in
: lumen output.
:
: But all this is based on the human eye, which is most sensitive to about 540 nm or
green
: light. You do not see red or blue light well, so when dealing wit actual light output
one
: needs to look a "Einstein's", a true light measurement of all light. Or a SED(
Spectral
: Energy Distribution ) Curve ( you know that nice colored rainbow plot you see on some
: light bulbs)
:
: Watts / gal is a MEANINGLESS value !! Why ? How deep is the tank, how wide is the
tank,
: what kind of bulb ( NO, VHO, CF, MH, MV, as they have a different "Point Source") and
K
: value, what is in the tank, etc..
:
: