On Nov 4, 5:34*am, wrote:
The use of a high quality filter is very important to the health of the the
aquatic system you are maintaining, but is only part of a total system. The
filters purpose is to remove particulate matter down to 5 or 10 microns, and
in the case of extremely fine filters (such as DE filters), possibly as low
as .5 micron. This accounts for anything that you may be able to detect with
the naked eye, and possibly even particles too small to see without a very
strong microscope.
Unfortunately, the need for further cleaning, into the sub micron and even
molecular level is still required to maintain healthy fish. Remember, your
fishtank is a complex ecosystem, complete with a full cycle of biological
actions, and chemical reactions. It is only as good as the weakest link in
the system. In this case, the parts that would remove the Nitrates from the
system (plant life), and the viruses (sunlight or ultraviolet light).
Because it is almost impossible to maintain a full system, these parts get
out of balance. They build progresibely, till they reach toxic levels.
Nature tries to find a balance of her own, which in this case calls for
reduction of the animals at the top of the system - your fish! They suffer
terribly from high concentrations of harmful bacteria, viruses and molecular
chemical polutants. Problem is, they do require some of the molecular and
submicron sized parts of a normal water column to thrive and survive. This
precludes the use of super purified water. If you were to use water that had
been run through a reverse osmosis system, or worse yet, a distillery, your
fish would perish very quickly. The water would lack the trace items
necessary for good health. Balance is the key here. The water that comes
from most municipal water supplies, and even most well systems has been
filtered to just the right level of purity for living things, including
yourself. Harmful concentrations of chemical toxins are at acceptable levels
(hopefully), and most viral and bacterial agents have been killed. They most
likely contain trace minerals (required for good health), as well as
acceptable levels of microscopic organisms. This is normal. If you read a
report of the local water systems content, you might cringe at the thought
of drinking it. No need to worry though, your body has a strong enough
immune system to handle these pollutants, as do your other pets and your
fish.
The main thing these water changes provide is dilution. You are merely
changing the ratio of polutants to acceptable levels. From that point, your
fishes biological systems can take care of the rest
I have learned a lot by reading this newsgroup, and I'm happy to say my
fishes, Sharky and Gemini are over three years old, 18" long and as happy
and playful as the day we got them. They managed to survive as the result of
what I've learned from the people on this newsgroup, and I am most grateful
to all who have helped me over the years. These fish have become great
little "Friends", and they even show affection by swimming into my hands
when I work on their tank. They really do mature, and develope unique
personalities! Worth every minute of time I have devoted to them.
I'll end with the most important quote I heard on here, and it was from
Ingid (of course) "The solution to polution, is dilution". Best medicine out
there is prevention.
Hope this helps,
Kevin

--
The information offered in this post is offered in the spirit of trying to
help. This is in no way a claim to be an authority of any kind on any
subject.

Well as much as there is a lot of good info in this post the thing
about adding salt as suggested is not a good idea as salt never leaves
by evaporation so it can build up in levels that are toxic to a fish
and the same thing goes ina marine aquarium toomuch salt can be toxic
to a sla****er fish. Only add what you can test for. If you can not
test for that substance then do not add it. Sooner or later you will
be biten inthe backside with arbitrarily adding salt. Refractometers
are dirt cheap to buy but some models may bot go down low enough to
detect ideal amounts.

One way to be safe or at least safer with using salt is to intially
add the amount needed for the gallons of your water. Then always top
off the tank or pond to that exact level, before doing a water change.
Remove "X" amount of water hwich will contain salt. Add back that
exact amount of water with the amount of salt in that fresh water to
equal what you originally had the salt level to. It will wind up
alwfully close, and much closer and safer than arbitrarily adding salt
back without some measure of quanity to guide you.