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Hot PCFs! Boiling Water!

The PC bulbs are about 35% efficient as I recall.  The Ballasts AH 
supplies are 90% efficient, so about 70 of the watts of your system is
being converted to heat.  Fans on the hood should  help by removing
much of the heat before it radiates into the water.  Then general rule
on fan placement is, place the fan so that it blows first on the hot
end of the bulb and blows along the length of the bulb.  This prevents
the chance of over-cooling the "cool" end of the bulb and reducing the
bulb's efficiency.  Ideally the fan should blow mostly through the area
just below the bulb(s)--otherwise the bulb and socket assembly impedes
much of the air flow.  Remember, the area of the blades near the tips
move abut 80 % of the air, so a 4" diameter fan moves much more air
than a 3" fan, other things being equal.

Try mounting the ballasts outside the hood, although this will have
only a small effect -- on a 96watt bulb, the ballast only produces
about 10 watts of heat; the bulb produces over 60 watts of heat.

Lower the ambient temperature if you can. For my own case, the room
mustn't be higher than 78 degrees F.  Below an ambient room temp of 76
degrees F, with the tank lights on, no other heating is necessary to
maintain the water at 78 degrees F.  Below 76 and additional heating is
necessary.  Above 78 degrees, the tank temp rises with each degree
increase in room temp and the rate of increase rises with the increase
in temperature.  At 78 degrees, the tank temp reaches about 82 degrees.

Raising the hood at least several inches up off of the tank can help,
but if you are fan cooling, it can affect the airflow.

Use a smaller pump or fewer pumps (incl. filters).  Virtually all of
the watts consumed by these ends up as heat in your tank -- although
the wattage here is substantially less than the the lights--unless you
have one hell of a current. :-)

Last resort would be to use an electric chiller.  These come in
completely solid state (except for a fan), which can accommodate small
jobs and freon-compressor types.  These are very expensive to obtain
and very large consumers of electricity.  The freon compressors will
not be silent.

Scott H.

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