Water Changes and Nitrate

My ammonia and nitrites test out at zero, so my bio-wheel biological filter
seems to be working well. I'd like to figure out how often to perform
partial water replacements based on the nitrate levels. At what level of
nitrate should I do a water change, and what level should I try to bring the
nitrate down to?

Thanks,
Dave

"David J. Braunegg" wrote in message
...
My ammonia and nitrites test out at zero, so my bio-wheel biological
filter seems to be working well. I'd like to figure out how often to
perform partial water replacements based on the nitrate levels. At what
level of nitrate should I do a water change, and what level should I try
to bring the nitrate down to?

Thanks,
Dave

It depends on size of tank and fish. A samll tank under 20 and large tanks
with messy fish may be 30/40. The lower the better. Some fish like angels
need regular water changes, 2 or 3 a week as they thrive in claen water
rather than the nitrate level. I do 2 x 10/15% a week on all my tanks, as
it prevents problems rather than spotting them later. In my 65g with 2
angels and 5 clown loaches they just deserve the best I can offer them, and
they are all thriving and growing. Some LFS say 10% a week or 20% a
fortnight, that that is a minimum/general rule and it's up to you to decide
based on your fish. Mary.

Mary,

Thank you for the response. I can see that that the desirable nitrate level
might vary by the type of fish, but the size of tank shouldn't matter.
Nitrate level is nitrate level no matter how big or small the tank is.

I have Platys and Corys. I've had several unexplained fish deaths and am
trying to figure out what is going on. I've seen no visible signs of
disease, so I am looking into water quality.

I have a 10-gallon tank and, due to a busy schedule, I shifted from a
3-gallon water change (with gravel vacuum) every week to a 3-gallon water
change every two weeks. I want some way of determining if I need to go back
to the weekly changes. I am also starting to wonder if I've been
overfeeding the fish. I am thinking that a high nitrate level would also be
an indicator of that. Hence my original posting.

Dave


"Mary Burns" wrote in message
...

"David J. Braunegg" wrote in message
...
My ammonia and nitrites test out at zero, so my bio-wheel biological
filter seems to be working well. I'd like to figure out how often to
perform partial water replacements based on the nitrate levels. At what
level of nitrate should I do a water change, and what level should I try
to bring the nitrate down to?

Thanks,
Dave

It depends on size of tank and fish. A samll tank under 20 and large tanks
with messy fish may be 30/40. The lower the better. Some fish like angels
need regular water changes, 2 or 3 a week as they thrive in claen water
rather than the nitrate level. I do 2 x 10/15% a week on all my tanks, as
it prevents problems rather than spotting them later. In my 65g with 2
angels and 5 clown loaches they just deserve the best I can offer them,
and they are all thriving and growing. Some LFS say 10% a week or 20% a
fortnight, that that is a minimum/general rule and it's up to you to
decide based on your fish. Mary.

David J. Braunegg wrote:
Nitrate level is nitrate level no matter how big or small the tank
is.

While this is technically correct I think what Mary was refering to is
that there is more room for error in a large tank. A high nitrate level
in a large tank isn't as serious because the increased water volume is
a bit more forgiving.

I have a 10-gallon tank and, due to a busy schedule, I shifted from a

3-gallon water change (with gravel vacuum) every week to a 3-gallon
water
change every two weeks. I want some way of determining if I need to
go back
to the weekly changes.

Unless your tank is very heavily stocked your current water changing
schedule should be sufficient for the fish you have. Have you tested
the water yet? If so posting some test results might be helpful.

I am also starting to wonder if I've been
overfeeding the fish. I am thinking that a high nitrate level would
also be
an indicator of that. Hence my original posting.

A high nitrate level is not necessarily an indicator of overfeeding. A
high rate of increase in nitrates would be though. If you want to use
nitrates to determine if you are overfeeding or not then you are going
to need to test the water several times between water changes to see
how fast the nitrates are going up rather than just finding out how
high they are now.

Also check your tap water - while you might think it should test 0ppm
for nitrates in many cases it does not.

-Daniel

In article , djb@reverse-the-
er.miter.org says...

I have Platys and Corys. I've had several unexplained fish deaths and am
trying to figure out what is going on.


Some corys (Panda for example) expire for little or no reason, never
happened to me but have seen reports.

--
Jim Anderson
( 8(|) To email me just pull my_finger

On 2005-04-05, dfreas wrote:

While this is technically correct I think what Mary was refering to is
that there is more room for error in a large tank. A high nitrate level
in a large tank isn't as serious because the increased water volume is
a bit more forgiving.


I'm not sure it is... It's harder to change a larger mass, but when you
test, you're testing the average, not a one time spike. That is,
overfeeding similarly stocked 20G and 55G tanks won't change the
water parameters in the 55G as much as the 20G. But, since the units of
measurement is ppm or g/mL, then the volume has been normalized.
It's that many ppm regardless of the size of the tank.

To answer the original question, the nitrate levels depend on what
you are keeping. Some fish can stand higher levels, others can't.
Plant tanks need higher levels to feed the plants. If you don't have
plants, ideally, you probably want nitrates to be as low as possible,
10ppm or less, maybe?

My favorite trick is to use terrestrial plants to suck out the nitrates
in a tank. Devil's ivy is particularly good for this. Let the leaves
hang outside of the tank, and immerse the root and root stubs in
the water. Something else to try is to find some aquatic plants
that are nitrates sponges like anacharis, duckweed, indian fern, etc.

--
"I have to decide between two equally frightening options.
If I wanted to do that, I'd vote." --Duckman

"David J. Braunegg" wrote in message
...
My ammonia and nitrites test out at zero, so my bio-wheel biological
filter seems to be working well. I'd like to figure out how often to
perform partial water replacements based on the nitrate levels. At what
level of nitrate should I do a water change, and what level should I try
to bring the nitrate down to?

Thanks,
Dave

Platies are good eaters, pecking plants during the day, eating the micro
(something) that feed on algae on plants. They do produce a lot of poo. In
my 10g, I am raising 10 male redwags platy fry for LFS. All are now 1", and
will have to be 1.25" before they are ready. It is fully stocked, but I
hoover gravel 25% a week and change 10% a day. Nitrate is 12.5% and tap
water is 15%. Plants bring it down very well. In my 25g, I have 30+ platy
fry, all about 1/2" . As platies eat everything from the top, middle,
bottom you have to increase the water changes. It is hard to get food past
platies for your cories as they will eat it first, before the cories come
out. My platies love tossing an algae wafer around, meant for someone
else, etc. Even so, platies are very hardy with nitrate levels, but your
cories are not.I have over 60 platies and 10 cories in various tanks at
moment so I do understand them a little. Mary

js1 wrote:
I'm not sure it is... It's harder to change a larger mass, but when
you
test, you're testing the average, not a one time spike. That is,
overfeeding similarly stocked 20G and 55G tanks won't change the
water parameters in the 55G as much as the 20G. But, since the units
of
measurement is ppm or g/mL, then the volume has been normalized.
It's that many ppm regardless of the size of the tank.

It isn't the nitrate levels directly that kill fish - nitrate levels
only stress them except at extreme levels (beyond the range of store
bought kits) where they can sometimes be lethal. In common practice it
is never the nitrates that kill a fish, the nitrates only stress them
and weaken them so they are more prone to disease. In a ten gallon tank
this is more dangerous than in a 100 gallon tank because the fish are
in closer quarters and disease will spread faster and more completely
giving a higher chance of killing the fish. So yes, high nitrate levels
are more dangerous in a small tank than in a large one. Normalization
of the volume has nothing to do with it.

pH fluctuations would also be more dangerous in a small tank - as would
wide temperature variations. Both of these are normalized parameters.
Neither of them however will kill fish directly except in extreme
circumstances, it is the stress they cause that weakens fish to attacks
from other dangers. Stress of any kind is in general a bigger risk in a
smaller tank.


Plant tanks need higher levels to feed the plants.

This isn't true. If the nitrate levels aren't zero then the plants have
plenty of nitrates. My tanks never get above 10ppm and they are heavily
planted - in fact I have successfully kept planted tanks with less than
5ppm (lower than the detectable range of the test kit) nitrates with no
problems whatsoever. The amount of nitrates that plants require is very
low and if nitrates aren't zero then the plants aren't using all of the
available nitrates and thus aren't starving.

-Daniel

In article , js1
wrote:

On 2005-04-05, dfreas wrote:

While this is technically correct I think what Mary was refering to is
that there is more room for error in a large tank. A high nitrate level
in a large tank isn't as serious because the increased water volume is
a bit more forgiving.


I'm not sure it is... It's harder to change a larger mass, but when you
test, you're testing the average, not a one time spike. That is,
overfeeding similarly stocked 20G and 55G tanks won't change the
water parameters in the 55G as much as the 20G. But, since the units of
measurement is ppm or g/mL, then the volume has been normalized.
It's that many ppm regardless of the size of the tank.

Agreed, although a ppm is a mg/L ... if you had g/mL levels of nitrate
in your tank, the water would be pretty sludgy!! (Saturated NaCl is
about 0.35 g/mL)

The flip side is that the volume of water needed to reduce nitrate
levels through water changes is slightly more than double for a 55g
versus a 20g tank - much more work unless you have everything plumbed
right in. I have a 130g tank here, and a 10-20% water change is a
BIG job!

"David C. Stone" wrote:
The flip side is that the volume of water needed to reduce nitrate
levels through water changes is slightly more than double for a 55g
versus a 20g tank - much more work unless you have everything plumbed
right in. I have a 130g tank here, and a 10-20% water change is a
BIG job!

Get a python water remover/replacer - its a doddle!