Yamato Green Fe
Yamato Green Technical Specifications
Terms & Conditions
Starting a Planted Tank
Plant Nutrients 101
Phophates in the Planted Tank
Fertilizer & the Planted Aquarium
CO2 & the Planted Tank
Safety Around the Aquarium
Cleaning Aquarium Glass
Mysterious Fish Deaths Explained!
New Tank Syndrome
Choosing an Aquatic Heater
Tips for Beginning Fishkeepers
Salt in the Aquarium
Outdoor Patio Tubbing
Malaysian Trumpet Snails
Buying and Installing an Aquarium Heater
by 2manyfish - September 1999
Heaters are mandatory on tropical fish tanks
unless you happen to live in the tropics. Except for a few notable exceptions
(Goldfish, Koi, White Cloud Mountain Minnows, Lemon Barbs, Peppered Catfish,
and a handful of others, which prefer cooler water), the majority of
tropical fish prefer temperatures of at least 74 degrees and preferably
a little higher.
Although hardy in most other respects, Livebearers such as Mollys, Platys
and Guppys, really don't tolerate water much cooler than 77-78 degrees.
Mollys and Platys in particular actually thrive in 80-82 degree water.
Many disease and parasite problems common to Mollys can be eliminated
simply by raising the water temperature to about 80-82 degrees. Some
other fish that prefer water in the 80-82 degree range would include
Betta splendens (Siamese fighting fish), Trichogaster leeri (Pearl Gouramis),
Pterophyllum scalare (Angelfish), Epaizeorthynchus (Labeo) bicolor (Red-tailed
Black Shark), Hemigrammus rhodostomus (Rummy-nosed Tetra), Metynnis argenteus
(Silver Dollar), and Botia macracanthus (Clown Loach).
It is also important to remember that whatever temperature you choose,
it should not fluctuate by much over 24 hours. If your aquarium room
is warm by day and cool (or cold) by night, a smaller fish tank can experience
wide temperature swings of 6 to 8 (or more!) degrees from the hottest
part of the day to the coolest part (usually early morning). Although
these temperature swings may remain within the limits of recommended
temperatures for the fish, this can be very stressful to some tropical
fish, and may account for some otherwise unexplainable mysterious fish
deaths. It is preferable to not allow temperatures in a tank to vary
by more than 1 or 2 degrees over a 24 hour period. Thus, if your room
in which your aquarium resides is warm by day and your tank temperature
would normally run, say, 78 degrees by late afternoon, then a heater
should be used to maintain (at least) that temperature during the entire
24 hour cycle, including the coolest part of the night.
There are some important differences between brands and models of heaters.
Almost every heater includes a little neon indicator light to show when
it is working. The glass tube that is the main body of a heater is constructed
of borosilicate glass, which resists heating and cooling without cracking
better than ordinary glass. Cheaper low priced heaters generally use
thinner glass walls in the tube. This makes them more fragile than heaters
with thicker glass walls.
The electrical circuitry inside the heater is usually controlled by
a bimetallic thermostat with a pair of electrical contacts mounted on
the metal strips. Quality of these contacts is very important. Good heaters
use German coin silver for their contacts. Silver contacts tend not to
stick together, and make excellent and reliable electrical contacts.
If you can find them, gold contacts are the best, but such heaters would
be very expensive. Cheaper heaters may use unknown metals that may not
function as reliably. To generate heat, all heaters use some arrangement
of nichrome wire through which electricity is passed. The wire warms
and the heat is transferred to the glass tube, and from there to the
water. Better heaters use sturdier wire for longer lasting life.
Whichever heater you choose, it is wise to mount it close to fast flowing
water (beside the filter outlet is a good choice), so water is constantly
circulated over the heater. Some heaters come with little rubber or plastic
suction cup devices to firmly secure the heater in position. This prevents
the glass in the heater wall from accidentally striking the tank wall,
which could potentially result in a fracture in the heater's glass, destroying
it. If your heater did not come with such a mounting device, Lee sells
heater mounting suction cups as an accessory item. Large fish (such as
Oscars and Goldfish) can easily slam heaters around, so be sure to mount
Heaters are rated by how many watts of electricity they consume. "Watt" is
right for your tank? Well, a useful rule of thumb is to allow about 5
watts per gallon of water in an average room where the desired temperature
of the tank is about equal to or less than 10 degrees warmer than the
room. If you are attempting to run an aquarium at, say, 80 degrees while
room temperatures dip to 50 or 55 degrees, then it might be better to
increase that recommendation to 10 watts of heater per gallon of water.
(Frankly, I have found the 5 watts per gallon rule to be extremely conservative.
It would only be in an extreme situation where a larger heater would
be required.) It is always a good idea to have a heater that is rated
as adequate or slightly more than adequate, as compared to a marginally
rated heater. A marginally rated heater may have to run constantly to
barely maintain the desired temperature, and would have no reserve capacity
should the room chill down a little lower than expected (such as when
that furnace decides to fail on a cold winter morning). A heater with
adequate capacity and a little reserve capacity will not have to cycle
nearly as often to maintain the desired temperature, and will thus enjoy
a longer service life. It will also be able to handle that rare and always
unexpected demand for more heating capacity should room heat fail.
Some people recommend dividing the wattage between two heaters. For example,
if you were running a 20 gallon tank and, using the 5 watts per gallon
recommendation, decided you needed a 100 watt heater, some would recommend
that you run two 50 watt heaters rather than a single 100 watt heater.
They reason that in case one heater fails, the other would be able to
pick up at least part of the slack and not let tank temperatures plunge
too drastically before you could catch the error and you could secure
a replacement heater. (People living in very cold climates should ALWAYS
keep a spare heater or two on hand, just to handle potentially disastrous
emergencies such as this.
A spare heater on the closet shelf is very cheap insurance if your tank
full of expensive fish should suddenly be endangered by heater failure
on some cold winter Sunday morning, when you might not be able to secure
a replacement right away.) By dividing the heaters into two heaters,
the reasoning continues, it also helps prevent the heart-breaking experience
of a heater thermostat sticking in the "on" position, and thus
cooking your fish. If you are in this hobby long enough, sooner or later
you will either meet someone who has had that experience, or (heaven
forbid) you might go through it yourself. Dividing the wattage between
two heaters seems to make sense.
On the other hand, high-quality heaters made today (Ebo Jager, Rena
Cal, others) enjoy very high quality construction with outstanding reputations
for reliability and very low failure rates. I personally own a high quality
heater (that, unfortunately, is no longer being manufactured) that has
been in continuous service since 1962 and is still going strong 37 years
later (as I write this in 1999). Paying a few dollars more for a heater
may be all you need do to protect against unexpected disasters in your
Some, such as the Heetmaster, are very easy to open and service, so
you can inspect and clean (or replace!) electrical contacts or components
if needed, something not every heater allows. Should you decide to attempt
to clean your heater's electrical contacts, do so by gently swiping a
piece of typing paper between the contacts. Never use an abrasive cleaner,
and never use anything hard (like a file), which can severely damage
electrical contacts. Exception: electronic supply stores sell a fine
little instrument called a Relay Contact Cleaner. This is a smooth little
band of metal mounted to a little handle, specifically designed for cleaning
and polishing delicate electrical contacts. It is similar to a file,
only with an extremely fine texture to it, almost the same as Bond Paper.
It will not leave metal filings or other residue which later could cause
electrical contacts to stick and the heater to remain stuck in the ON
position. No submersible heater is easily opened and serviced, so it
would probably be wise not to try. If you don't get the seal exactly
right and water enters the heater, the heater will be ruined very quickly.
If you weren't already aware, NEVER put a heater in water unless it
is unplugged and has been allowed to cool to room temperature first.
The combination of hot glass in cold water can have spectacular and disastrous
results. After placing the heater in the water, allow temperatures to
stabilize for at least 5 or 10 minutes before plugging the heater in,
also to prevent unnecessary glass breakage. Always inspect a heater for
almost unnoticeable cracks in the glass before placing it in water. A
hairline crack in the glass can result in catastrophic failure at a later
date. Be very careful in handling the heater not to strike the glass
against a hard object. Never clean a heater's glass with anything that
might scratch the glass, which could cause it to fracture along the scratch
line at a later date.
NEVER put your hand or arm in an aquarium with a heater plugged in.
Should there be any electrical leakage, it could really ruin your day.
Should your heater's electrical cord develop any hint of a cut or damage
to the wire's insulation, play it safe and remove the heater from usage
at once. Never attempt to repair the electrical cord by taping or by
applying any insulating wrap - it's just not worth the risk to fish and
fishkeeper. Either return the heater to the manufacturer for servicing
and replacement of the wire, or discard the heater.
Most heater manufacturers picture their heaters mounted vertically on
the tank. Of course, non-submersible heaters demand this mounting, and
you CAN use a submersible heater this way. Used in this position, convection
currents produced by warm water rising off the heater will tend to cause
greater temperature shifts from one area of the tank to another. Without
supplemental circulation, water on the right side of the tank will tend
to be measurably cooler than water on the left side of the tank. There
is also the problem of "layering," where warm water tends to
rise to the top of the tank, leaving water at the bottom of the tank
However, you can take advantage of a submersible's slightly greater
efficiency for heating (because no heat is wasted through the exposed
assembly out of water column at the top of the tank if a heater is submerged),
and also improve water circulation. Simply turn the submersible heater
on its side, mounting it close to the bottom of the tank, like this:
| | |
| \========o |
In this position, all the heat produced by the heater will go into the
water column, and none directly into the air above the tank. (A glass
cover will help to hold heat inside the tank where it belongs, and not
allow it to escape into the air above the water. Evaporation is also
reduced with a glass cover.) Water circulation will be improved in the
tank because convection currents from the heater will gently stir up
cold water from the bottom of the tank as warm water rises off the heater.
You will see much more even heating in the tank by using a submersible
heater in this manner. Another advantage comes at tank water changing
time. If you have a vertically mounted heater and forget to unplug it,
you can drain water down until the glass around the heater element is
exposed to air. When you refill with water, it is possible to fracture
the glass in the heater's tube. In my humble opinion, horizontal mounting
is the preferred mounting for a submersible heater. Again, before mounting
or moving any heater, first be sure the heater is unplugged. Remember,
heaters operate from 115 volts (or 230 in Europe!), and your hands are
wet. By unplugging the heater before handling, you eliminate any danger
of electrocution or dangerous shock.