Measurement:
Chlorine (Cl), measured in ppm, is a gas which has been added
to tap water to control harmful bacteria. City provided tap
water is normally found to have 0.5 - 3.0 ppm but higher
surges are sometimes observed. Some city water supplies can
still be found that either do not require chlorination or may
have the chlorine removed before the water is distributed.
This would not be of concern to those who take their tap water
directly from a private well. Droplet and pill test kits are
available. Recommended test kit range 0 - 4 ppm. A chlorine
test kit is not considered necessary for the average pond.
Acceptable concentration 0
Effects:
Chlorine is a quick killer in fairly low concentrations (less
than 0.5 ppm). Even in very small concentrations, it burns the
edges of the gills with long term after effects. It also can
be deadly to the bio-converter bacteria.
Treatment:
In an open container, water will release about 1/4 of the
chlorine concentration per day to the air . Water that has set
in an open container for a week or just for a couple days if
aerated, is normally safe to use or better yet, pre-treat tap
water with one of the commercial chemical products. Follow the
manufacturer's directions (Or make your own).