Re: More on Heat Tape

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

Roxanne Bittman reported success with a simple arrangement of a
rheostat and 11 inch wide heat tape.  For those unfamiliar with this
stuff, it comes also in 3 inch widths (10 watts per lineal ft), 4"
width (8 watts per lineal ft). The 11 inch Heat Tape is 20 watts per
lineal ft).  The actual watts per lineal foot can vary depending on the
supplier but those are typical ranges.  So you can mix and match to
cover your bottom, if you will excuse the expression.  Also, you can
connect them in series if you want to reduce the total wattage -- use
the Ohm's Law formula to calculate.  If you connect them in parrallel
(electrically but not necessarily spatially) you can count on the rated
watts per foot for each piece.

Since these are simple resitor heaters, you can use a rheostat or an
incandescent bulb dimmer switch to adjust the constant heat level.  If
you need to shut off the heaters, for example, during the summer
daytime when the lights and ambient temperatures give your tanks more
than enough heat, you can try using a timer switch in the circuit to
feed the "rheostat" or use get a thermostatic control to automatically
maintain a constant temperature.

Heat tape is not recommended for use where it will be totally enclosed
without any airflow.  So if you put it on your tank bottom, you might
want to leave the area immediately below the tape open to the room air.
 Since the tank is filled with water, which conduct heat reasonably
well, I would not expect a dangerous heat build up below an aquarium
with heat tape attached.  But consideration, if not caution, are
probalby advised.  Also, a broken tank or inadvertant deluge for some
other reason, heaven forbid it should really happen, could get the heat
tape connections wet, so be sure to use a Ground Fault Circuit
Interrupter (GFCI) on the heater circuit.  But then, all your aquatic
electrics are on GFCI circuts, right?

Also, it's *not* recommended that you sandwich two or more layers of
heat tape together to get more watts per foot.

Scott H.

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