"Reel McKoi" wrote
Also, to the original poster, you should find out if your municipality
uses chloramine instead of just chlorine in your tap water.

The chlorine will
dissipate fairly soon. The chloramine will not and it needs to be
treated.
See this for more than you'll ever want to know about the subject:

http://www.reefkeeping.com/issues/20...ture/index.php



Municipal water systems are required by the EPA in the USA to disclose the
chemicals used in their water treatment processes must publish this
information each year for its customers.

For instance, here in New Orleans, the Sewerage and Water Board publishes a
booklet annually that describes what they do (see
http://www.swbno.org/waterpurification.html and
http://www.swbno.org/wq2006rptinframe.html ). Here's an exerpt:

"The raw river water is treated with chemicals called "coagulants" which
cause the small particles in the water to come together to form larger
particles which are then allowed to settle out of the water. Rapid sand
filtration is used to remove even smaller particles. During the process
chloramine is added to disinfect the water. Lime is added to provide
corrosion control and to increase the pH of the water to stabilize the
disinfectant. Fluoride is added to prevent tooth decay."

The coagulants used are polyelectrolites and ferric sulfate, both of which
are almost entirely removed during the initial coagulation (flocculation)
processing. Lime is added to increase the pH level of the water and to
stabilize the disinfectant. Later, free chlorine and anhydrous ammonia are
added to produce the disinfectant chloramine (technically that's soldium
hypochlorite NH2Cl)). Sodium hexametaphosphate is added to keep the lime in
solution. The flouride added is fluorosilicic acid.

This process is not unlike that used in many cities. The separate addition
of the chlorine and ammonia to produce chloramine is typical and effective
because chlorine is dangerous to transport and chloramine is more stable as
the water is distributed. However, as "Reel McKoi" says, it has to be
treated with commercial chemicals (generally sodium thiosulfate) before
introduction into the pond.

For some interesting info on chloramines and fish culture, see
http://www.skepticalaquarist.com/doc...chlorine.shtml ).


Michael
New Orleans, Louisiana USA
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