Re: Bulb Question

>From: John Lobingier <jlob at wpa_net>
>Are actinic bulbs ok to use in a freshwater plant tank?  I want to put in
>some red plants and one actinic bulb was recommended for them. Do red plants
>like a lot of blue light?  So that this bulb does not give me a blue tank
>using one "red" and one "50/50" bulb was recommended to offset the actinic.
>How does this sound?  What bulbs are considered "red" bulbs?  Other than
>Coralifes 50/50 bulb, what are some other bulbs that fit the 50/50 bill?
>Thank you in adavance for the help.  

I may have over-simplified to the point of inaccuracy in a few places, but
please bear with me.

IMO, 50/50 and other actinic bulbs are much better for a reef tank than they
are for a plant tank.  If you want a high-intensity blue bulb, I'd recommend
the Penn Plax Ultra Trilux.  I have one of these, and it's a very bright
whitish blue.  

After having spent mega-bucks on the tri-phosphor aquarium bulbs (Triton and
Penn Plax Ultra Trilux), I've discovered commercial lighting vendors (kudos to
people on this list for pointing them out to me).  Grainger is one, but they
only sell to companies.  You can look in the yellow pages under lighting and
should be able to find a lighting place that will sell you the 5000K blue tubes
that plants love (GE Chroma 50, GE SPX-50 are examples) along with electronic
ballasts, etc. for pretty reasonable prices.  If you switch to electronic
ballasts and T-8 tubes instead of the older style T-12 tubes, you can pay
roughly $7.00 per tube and expect them to last a year instead of only 6 months,
plus T-8 tubes are 20% brighter than most T-12 tubes.  Compact fluorescent
tubes can also be a good way to mix up a good spectrum, but they're more
expensive, at $7.00 per 13w tube and $6.00 per single tube 13w ballast.

I prefer a pretty balanced spectrum on my tanks.  I tend to go with 1/2 - 2/3
in 5000K lighting, although I've also used Power-Glo tubes with quite a bit of
success, and 1/4 - 2/3 in 2700K lighting.  It's important to get a good CRI
number (color rendering index) if you use the 2/3 - 1/3 formula.  The extra
missing quarter goes to a tube in the red spectrum, like a GE aquarium and
plant tube (probably 1500K - 2000K).  I've tried the phillips grow lights and I
hate them.

I've found that too much red or yellow in the spectrum tends to encourage red
algae growth, so I definitely try to lean towards the blue, but I really like
the additional yellows that you get with an added 2700K tube.

When I use the term K, I'm referring to color temperature in Kelvins.  This
measures the bulb spectrum as it compares to the radiance of a black body at
that particular temperature measured in Kelvins.  The higher the CRI, the
closer the color rendering is to a true black body spectrum.

David W. Webb
Enterprise Computing Provisioning
Texas Instruments Inc. Dallas, TX USA
(214) 575-3443 (voice)  MSGID:       DAWB
(214) 575-4853 (fax)    Internet:    dwebb at ti_com
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