Re: heater size/configuration

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

turnerjo&blair asked about right sizes, and good brands, of
heaters, particularly for a 100 gal. tank.


I offer this:

Figuring the right size heater can be as detailed a job as
figuring out the right lights to buy, excpet that too much
is much less likely to cause problems.

Tube heaters with internal thermostats often require long
periods to stabilize, this because the heater heats the
thermostat directly as well as via the water.  So it keeps
cycling itself off until a stabile conditon is finally
reached.  This helps to prevent overshooting by the heater.
 But I never liked the technique; I've always preferred
thermostat sensors that could be placed remotely from the
heat source.  There was a time when thermostats were
seperate items; you opended them up and adjusted them with
a screwdrivber.  The internal thermostat was a big step
forward in heater design -- one less tube in the water.

Nowadays, you can get sensors the size of cigarette butts
on separate controllers.  You can even get tube heaters
that have remote sensors (check out, for example
ThatFishPlace and, I thnk, Aquabotanic).  I personally
recommend such heaters but the "regular" type work okay
too.

I have recently had good experince with the 
"Electronic Heater 300 Watt W/Probe (Jalli)" from
ThatPetPlace.  In a 100 gal, I would probably put 2 200
watt heaters rather than one 300 or 400 watt heater (Yes
you can get individual metal tube heaters that go up beyond
300 watts, all the way to 800 watts).

Really hot heaters might be better placed in a sump for
obvious reasons.

Scott H.

Heater placement and water flow can have dramatic effect on
efficiency.  The lower the heater is placed, the better. 
The closer to a current source, often the better.  The idea
is to avoid having the heater high and/or in a relatively
stagnant location -- under those conditions, the heat tends
to rise to the top of the water column and leave the tank
without spreading around much and doing much good.

I have used 200 watt substrate cable heaters in my 150
gallon that did a fine job of maintaining water temps
around 79 in room where ambient temps are about 65 degrees
F during the night.  In that same tank, under the same
conditions, I need over three times as many watts is I use
glass tube heaters.

In any case, with glass tube heaters, I prefer two smaller
ones to one large one -- a device failure is a total failure.

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