Sue,

I would say you have been mostly lucky. Chlorine and chloramine are
oxidizers similar to PP and as such they are spent digesting bacteria and
other things in the pond in fairly short order. The problem comes in that
the amount that is added is usually added faster than it is consumed and the
chlorine/chloramine build up to a measurable level and start to burn the
gills of the fish. For small water additions, of less than say 5% then the
amount that is able to build up in the system is small enough that it
probably doesn't harm the fish. Doesn't do them any good either. The
chlorine will work on the bacteria in the filter system, setting it back
from a little to a lot, depending on the amount of water added and
chlorine/chloramine level in the water. I don't care how much water I add,
I always add dechlor. I have the automatic fill valve, but have never
gotten around to using it. It fits behind the filter pad in my skimmer and
when the pad gets clogged, the water level behind the pad falls, so it is
possible to overfill a pond.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html


"Sue Alexandre" wrote in message
news:kLtEa.14361$_Z1.5689@lakeread04...
Now I'm starting to worry about something I've never had on my "worry
list"
before. I've NEVER added anything like dechlor to my pond, and I do
partial water changes and topoffs often. The pond is about 4000
gallons,
and every time I do a skimmer/pump/filter cleaning (about every week or
maybe a little less) I let a lot of water run out of the pond. I let it
go
down 4 or 5 inches at these times, and when I was installing the skimmer a
month or two ago I let a LOT more out than that. Then I fill it back up
with the hose and don't worry about it. I've never lost a fish, and the
water looks clean and clear 80% of the time. Should I be worried, or is
there enough volume in my pond to dilute the topoffs?
Sue

"Nedra" wrote in message
thlink.net...
But would it not depend upon how Much water is being
topped off?? I think I would add some DeChlor every
other day or so- just to be sure the Chlorine wasn't poisoning
the pond.
FWIW....

Nedra
http://www.geocities.com/Heartland/Pines/4836
http://community.webshots.com/user/nedra118

"John Hines" wrote in message
...
"Randy" wrote:

Does using an automatic water filler (which is constantly topping off
the
water level with city chlorinated water) mess with the bio
environment
of
our water or do we HAVE to use a charcoal filter?

I say no, because:

a) the amount of water topped off is small, per day
b) you specify clorine, and not the nastier cloramine