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Re: Lighting



>1)   Is having my T12 bulbs 7" above the surface of the water going to be
>too much light loss? How much will I lose? I have purchased some sheet
>aluminium to fashion a reflector. I probably can get it down to around 4"
>from the surface. Will making these adjustments make any signifcant impact
>on the lighting arrangement?

Depends a lot on the reflector. If you use a really good reflector that
directs the light pretty much straight downward I think you'll be OK.
You're higher for T12 lights than most though. I think a more usual height
for those tubes is some 2-3" or so. Lots of info on this on the krib too.

>2) I have designed it to use 6 bulbs for a total of 240 Watts. Is this
>enough for a 80 gallon tank? I'm actually using the measurment of a 70
>gallon tank as I have at least 4" of substrate and I'm sure that I lose 10
>gallons or more. From the tank surface to the substrate is 16.5  inches. I
>could still make the change and add in 2 more bulbs for a total of 320
>Watts. Would this be overkill?

All depends on what you want to grow ;-) Probably not enough for really
high light stuff, but probably OK for the lower light stuff. One of the
plant experts will probably add a lot more detail than I can provide on
this though.

>3) I have bought 2 3" muffin fans (cooling fans) to mount into the hood. I
>will wire them to go on and off with the lights. This should be enough
>cooling for 6-8 T12 bulbs?

You might not need anything beyond convection cooling. The fans are going
to help your tank to evaporate more water though, so I suggest making some
kind of lens (maybe some acrylic or something similar) so that you can duct
the airflow over the bulbs without picking up the humidity. This will also
help your electrical components in the hood last longer, and will allow
your cooling to operate more efficiently which means fewer fans and less
noise.

You would probably be OK just using some large vents in the hood,
especially if you are going to use remote-mounted ballasts.

     -Bill

*****************************
Waveform Technology
UNIX Systems Administrator