A "pond" is essentially a large outdoor aquarium.
It will benefit from 10% water changes weekly, to lower DOC, nitrates, etc,
that otherwise accumulate.
Plants help with some nitrate, etc removal, but water changes will remove
many other substances.
Water changes also replace water soluble minerals that fish need.
They are beneficial, as most running fresh/salt water systems will tell you.
Happy ponding,
Greg

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"claude rogers" wrote in message
...
Total water changes even split up day after are very risky at best, you
are
introducing new trace minerals in the water which may and probably will
affect you total system or balance. I have to agree with Jammer on this,
unless you trying to solve a problem, let sleeping dogs lye.

"Loretta,Victoria, B.C." wrote in message
...
The other day I pumped out about 4 - 6 inches of water from my pond and
then
refilled it. I did the same thing the next day. I wanted to get some
fresh
water in my pond and figured that was a better way than just overflowing
the
pond, which is what I did in the past. What I want to know is: how
many
days can I keep doing this without harming my fish? I would like to
keep
doing it until all the water has been exchanged without having to remove
fish from the pond and removing water all at once. Earlier in the
season
I
did some vacuuming in the pond and the bottom is fairly clean. But the
water has been in the pond for 4 years with only fresh water being added
when I overflowed the pond. Fish are fine and healthy and acting
normal.
The fish load is such that I think a total change of all the water would
be
a good thing.

--
~~~Politicians and diapers have one thing in common. They should both
be
changed regularly and for the same reason.~~~