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CF Lighting Recommendations Needed



James Purchase wrote:

I've been looking over the "CF Bright
Kits" offered by AH Supply and I'm
seriously considering chucking the 3
175W MH Pendants over my 130G, 6' long
tank
I know that the Watts/Gallon "rule" is
at best only a rough guide, but this
would work out to only 2.5 W/G, whereas
my MH Pendants (when they _worked_
properly) provided 4 W/G.

I think CFs are very useful but they are
really not much different than regular
NO fluorescent lamps. Fluorescent lamps
are the most efficient  at normal output
in longer lengths and in smaller
diameters.
Compact fluorescents are really small
diameter VHO lamps. So there is a loss
of efficiency because they are being
overdriven, a gain because they are
essencially 4' long and a gain in
efficiency because they are small
diameter lamps. You also pay a penalty
in lamp life when you fold the tube in
half. The ideal system for your tank
would probably be 4 pentron 54 watt 7500
lumen lamps. This is the equivilent of
about 9 48" T12 NO lamps or 7 55 watt
CFs. Although they are only available in
4100K color temperature I am sure it is
only a matter of time before something
more suitable comes along. This stuff is
supposed to be widely available in
Europe but has not really caught on here
yet. I bookmarked a link so you can look
at the lamp specs at
http://ecom.sylvania.com/osicatalog/mult
iresult.asp?Item=20865 . Now I bet these
are fairly expensive but maybe you could
be the guinea pig and try them out. It
is also too bad that you cannot get them
in 6' lengths.

The way to compare different fluorescent
systems is to compare lamps with the
same phosphors then you can base your
comparison on their respective outputs
in lumens. It is not possible to compare
MH lamps to fluorescents using this
method because there is no exact
equivilent of say a cool white lamp in
MHs. All I  can say is that 6 55 watt
PCs is the equivilent of about 8 40 watt
48" NO lamps. I have to think this would
be more than enough but probably not as
much as your MHs. It is just a guess but
the MHs when new could be the the equal
of about a dozen 40 watt NOs as they age
though they are going to lose about 20%
of their intensity within about a year
and a half.

Wayne Jones

Wayne's DIY Aquarium Setup at
 http://www.mnsi.net/~waj