Water Changes and Nitrates

I have a large tank with a light fish load. My nitrates are around
10PPM. Do you need to do a water change with such low nitrates?

When I had a heavier load I would water change enough to keep nitrates
below 40ppm but since my load is lighter the levels of nitrate are
taking much longer to rise.

Brian

Brian wrote:
I have a large tank with a light fish load. My nitrates are around
10PPM. Do you need to do a water change with such low nitrates?

When I had a heavier load I would water change enough to keep nitrates
below 40ppm but since my load is lighter the levels of nitrate are
taking much longer to rise.

Brian

You should do water changes no matter what your nitrate levels are. You
could go with a 15% every week or maybe a 25% every 2 weeks.

jake wrote:

Brian wrote:

I have a large tank with a light fish load. My nitrates are around
10PPM. Do you need to do a water change with such low nitrates?

When I had a heavier load I would water change enough to keep nitrates
below 40ppm but since my load is lighter the levels of nitrate are
taking much longer to rise.

Brian


You should do water changes no matter what your nitrate levels are. You
could go with a 15% every week or maybe a 25% every 2 weeks.


I'd say it was proportional to fish load, personally. You can get away
with water changes if your tank is planted. My CO2 injected, planted
tanks rarely need a change of water, only top-up from evaporation
required. The mass of plants act as a natural filter. It works for me.
My shrimp, which are coming up to 18 months, and a pair of Ancistrus
which has just spawned, are thriving in months old water. I have to add
nitrate and phosphate from bottled fertiliser, otherwise the plants suffer.

Nikki

"Brian" wrote in message
...
I have a large tank with a light fish load. My nitrates are around
10PPM. Do you need to do a water change with such low nitrates?

When I had a heavier load I would water change enough to keep nitrates
below 40ppm but since my load is lighter the levels of nitrate are
taking much longer to rise.

================
I do partial water changes no matter what the Nitrate levels.
--
KL....
Aquariums since 1952.
My Pond & Aquarium Pages:
http://tinyurl.com/9do58
~~~~ }((((* ~~~ }{{{{(ö ~~~~ }((((({*

Brian wrote:
I have a large tank with a light fish load. My nitrates are around
10PPM. Do you need to do a water change with such low nitrates?

Water changes not only lower the nitrAte level within the tank, but
also the DOC (Dissolved Organic Compound) level. DOCs are the uneaten
foods and fish waste within the tank that has decomposes/dissolved and
that passes right through the filter. A weekly 20% (or more) water
change is needed to keep the DOC level from accumulating over time.
Without the water changes, the water problems because of the DOC
build-up slowly deteriorates and the fish start to suffer from stress.
The build-up of DOCs also create conditions that encourage disease,
parasites and opportunistic bacteria.............
Frank (FB)

Can DOC (Dissolved Organic Compound) be measured in a tank?

Brian

"Frank" wrote:

DOC (Dissolved Organic Compound)

Yes it can but it is often easiest to do rather simple tests
Like check the colour against tap water
or even watch the ph drop
sure they aint scientific or accurate
But you probably do it without realising anyway
DOC are often 'mixtures' somakes it tricky to know what to measure
and once you have some results that doesn't help
as other chems are not in 'related' amounts
yea I butchered explaining that
but it ain't so much like the relationship between Kh and Gh and Co2 and
stuff
It's more just the fish soup
and everyones is different
water clarity is a biggie
but even so tis no sure fire
easier to just water change
or call your local water supply guy and get him to explain how he measures
it
will be a fascinating call I imagine
LOL
HTH's
:-)


"Brian" wrote in message
...
Can DOC (Dissolved Organic Compound) be measured in a tank?

Brian

"Frank" wrote:

DOC (Dissolved Organic Compound)

Brian wrote:
Can DOC (Dissolved Organic Compound) be measured in a tank?

You need a chemical hardness test kit and a conductivity meter. DOCs
are not detected by a hardness test, but they will measure on a
conductivity meter. A conductivity meter measures TDS (Total Dissolved
solids) - both hardness and DOCs. The difference between the two test
determine DOC. If you put off water changes (long enough), two things
can happen when you do get around to the water change.
#1 - Old Tank Syndrome - water change leaves the fish showing
immediate distress, gasping, lose balance, lay on side and die. The
cause - aged water slowly consumed carbonate buffer (low kH), and the
pH slowly drops. Toxic ammonia becomes non-toxic (ammonium) and builds
up. Then, with a water change, the buffer is suddenly restored.
Non-toxic ammonium reconverts back to it's toxic form ammonia, and the
fish die of ammonia poisoning...
#2 - Most likely to happen is Osmotic Pressure Shock. Without weekly
water changes, just topping the tank off, TDS levels get high. A water
changes lowers TDS too quickly and the fish suffer from osmotic
pressure shock. Osmotic shock interrupts healthy gill funtion by
reducing the intake of oxygen and releace of carbon dioxide and ammonia
from the fish. This can harm or even destroy the fishs
gills............... Frank (FB)

"Frank" wrote in message
ups.com...

Brian wrote:
Can DOC (Dissolved Organic Compound) be measured in a tank?

You need a chemical hardness test kit and a conductivity meter. DOCs
are not detected by a hardness test, but they will measure on a
conductivity meter. A conductivity meter measures TDS (Total Dissolved
solids) - both hardness and DOCs. The difference between the two test
determine DOC. If you put off water changes (long enough), two things
can happen when you do get around to the water change.
#1 - Old Tank Syndrome - water change leaves the fish showing
immediate distress, gasping, lose balance, lay on side and die. The
cause - aged water slowly consumed carbonate buffer (low kH), and the
pH slowly drops. Toxic ammonia becomes non-toxic (ammonium) and builds
up. Then, with a water change, the buffer is suddenly restored.
Non-toxic ammonium reconverts back to it's toxic form ammonia, and the
fish die of ammonia poisoning...
#2 - Most likely to happen is Osmotic Pressure Shock. Without weekly
water changes, just topping the tank off, TDS levels get high. A water
changes lowers TDS too quickly and the fish suffer from osmotic
pressure shock. Osmotic shock interrupts healthy gill funtion by
reducing the intake of oxygen and releace of carbon dioxide and ammonia
from the fish. This can harm or even destroy the fishs
gills............... Frank (FB)


yea, what he said!
:-)
As a side note 'osmotic shock' is how you 'wake up' things like brineshrimp
and triop eggs.
A good osmotic shock will give a higher hatch rate. Well thats the theory
anyway.... no real link to back that one up....

Nitrates are just one of the pollutants that you are water changing to
dilute.
That said you prob let it go for a lot longer with a small bio-load.
I try give all me tanks a 25% every week
yes thats a lot of water changes
but once your in the rythm it's kinda a workable method
Put it this way, it can't hurt to keep up the changes.
But you can get away with not doing them for longer
I have a marine tank that has been 6 months without a water change
nitrates are maybe 15ppm
But I do plan on getting stuck in a doing a nice big one next week
Is a tricky tank to water change is all
even so
zero cassualtys
I wouldn't reccomend others doing that but yea I have gotten away with it.



"Brian" wrote in message
...
I have a large tank with a light fish load. My nitrates are around
10PPM. Do you need to do a water change with such low nitrates?

When I had a heavier load I would water change enough to keep nitrates
below 40ppm but since my load is lighter the levels of nitrate are
taking much longer to rise.

Brian