Re: Question about lighting - or What's watt

["S. Hieber" <shieber at yahoo_com>]

Dave Clark asked:

> I'm a bit confused about lighting.  I know that
> florescent bulbs supposedly give out as much light as
an
> incandescent using less electricity.  Say a 20 watt
> fluorescent gives off the equivalent of a 100 watt
> incandescent (I have no idea if this is close).  Which
> wattage do you use when figuring how many watts are
> shining on your tank?

When you hear watts-per-gallon (wpg) given as a guide to
how much light a plant needs or how much light to try to
get onto your planted aquarium, you'll hear roughly 2-2.5
for relatively low light levels, 3-4 for high levels and
anything more than that is usually considered very very
high.

These wpg  values are for regular fluorescent bulbs in
unextraordinary fixtures.  Different ballasts, bulbs,
reflectors combinations give off different amounts of
useful light.  For example, an AH Supply kit will put more
light on your plants than an equal wattage of Perfecto
standard fluorescent fixtures.  Watts are like cologne.  A
lot more is not a lot better; it can easily be too much. 
And some folks do well with very little (low light, slow
grow tanks).
Unlike cologne, none at all is not a good option ;-)

Scott H.

Sometimes you can look up the data on bulbs and ballasts. 
Much harder to find data for reflectors or fixtures.

Few have actually measured, and reported the results for, a
lot of bulb/ballast/fixture combinations.  It's a sizeable
hole in the hobby.

You're sure to hear more from others.

Scott H.

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