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Re: T-8 Light and Ballast Questions



>I know these are the new energy saving bulbs.  Looking in the Pet Warehouse 
>catalog I noticed Sylvania makes a 36 watt 48 T-8 bulb which they say 
>consumes less wattage, and Zoo Med makes a 32 watt 48 T-8 bulb.  Are >either 
>of these the energy saving T-8s like the GE and Philips.  Are there any 
>other bulb options?

The standard wattage for a T8 tube is 32 watts. The 36 watt might (but not
sure on this) be some kind of retrofit for the old 48 watt T12 fixtures. I
have seen some "energy efficient" T8 tubes used commercially that I believe
are either 24 or 25 watts.

As for the specific bulbs you mention and the ballast factor, those are
Ivo's territory. There is a lot of info on the subject in the list archives
too from a few months ago.

>3.  As far as the wiring goes is there a primer anywhere on the web for 
>setting up your own lights?  I am concerned about the electrical safety 
>involved versus just buying a commercial light setup.  Maybe Im making >this 
>out to be harder than it is but I havent done anything like this.  I have 
>always used the strip lights that come with the tank.

There are some simple diagrams on the Krib. Most of the ballasts will have
the wiring diagram either silk-screened on them or on a sticker. You will
need an enclosure suitable for the ballasts (sometimes a hood will work if
there is enough room inside), and suitable wire to connect the ballast to
the light fixture. Flourescent fixtures should be wired with 105C rated
wire, which is type TFFN if I'm remembering right. The endcaps that "grab"
the wire want to see 18awg solid wire (tinned stranded will usually work as
well). Chances are you will need to get the wire from a commercial
distributor since the usual stuff in hardware stores is THHN which is only
rated for 90C. 

If you use a metal enclosure, it should be grounded (green wire or green
with a yellow stripe). If you use a plastic enclosure you don't need to
ground it, but you should make sure that there is no metal component
outside of the chassis that could conduct a current to the outside if
something should happen to the internal components. It will generally be
safer to use a grounded metal enclosure in DIY applications since you don't
have to worry as much. Be sure to fuse the HOT side of the power cord
(black wire).

If you use a seperate ballast enclosure, the best cable to connect it to
the fixture is type SJEOW or type SJOW, both of which are water resistant
cables that can be found in 105C versions. 

>4.  I know I will need a reflector.  Checking the Krib I saw everything >from 
>using mylar to white paint to aluminum foil.  I saw an Aqua Mirror 
>advertised in the Pet Warehouse catalog which says it is good for both T-8 
>and T-12 bulbs.    In an archived  post somone wrote that the best shape >for 
>T-8 reflector was the shape of McDonalds Arch and then putting the light in 
>the center.  This Aqua Mirror is definitely not that shape.  Would it still 
>be better than plain aluminium foil or mylar?

aluminum foil tends to degrade quickly in the humidity of a tank hood. I
usually only get about 6 months out of it in my cheapo home brew reflectors
until it starts getting holes in it. While it will still work (and I have
one that is 2+ years old), it gets crusty and holey and is probably not
very useful as a reflector. A bright white paint is popular inside of large
wooden hoods, and there is a lot of info about this on the Krib.

The Mcdonald's arch is an "ideal" reflector, with the bulb placed a bit
below the center point of the arch. I don't know of any commercial
reflectors made like this, but there are a lot of approximations made with
numerous flat bevels. Many of the metal halide reflectors use variations on
this design.

>tanks 
>and get rid of the strip lights for good.

Depending on the kind of hoods you have, you may be able to install new
lights in your existing hoods. You can get a very professional appearence
that way. I have done this with my two 20 gallon All Glass hoods to use the
AH supply power compace kits. Works great. I did install small fans on the
hoods to keep the temperature down though -- they don't have very much
cooling ability by themselves and the way the vents are don't permit very
efficient convetion airflow.

     -Bill

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Waveform Technology
UNIX Systems Administrator