> Gary's argument was simple: active, funtioning bio and/or plant
> filters will take up any ammonia as soon as it's released. Besides
> that, the amount released from the new water is quite small. I keep
> everything from rainbowfish, to South American and West African
> cichlids, to killies, to catfish, to Tanganyikan cichlids... many of
> which are highly sensitive to both chlorine and ammonia, esp the
> Tanganyikans. I have never, ever had a problem.
I agree 100%. That is the system I use too.
> So, to flat-out say that you cannot use a straight dechlorinator for
> chloramine-treated water is not necessarily true.
> >
> > 3.5 ppm = 35 g/L which is alot!
3.5 ppm = 3.5 mg/L! Sorry. My mistake.
Concerning plant/bacteria uptake of ammonia, only the
fast growing plants can generally do this. Such plants
are duckweed, all the floating plants and most of the
bunch plants. Oddly enough J. moss seems very effective
too.
On another note, unless your pH is high (8.odd) most of
the ammonina will be in the form of ammonium which is
less toxic than ammonia (as no doubt you all know). Dan
has a problem as his pH is around this mark...
Size of the water change is very important. With my
TAnganyikans I rarely change more than 20% at a time.
This way even if 3.5 ppm makes it into the tank it is
effectively only 0.7 ppm. Plants can quickly take care
of that if there is enough light and CO2. The odds are
your fish probably produce more ammonia than that in a
single day.
Concerning Cl's toxicity: I don't use dechlorinators,
even when I do 40% water changes. I am yet to of had
casualties. If you are only subject to plain Cl2 and are
doing a 40% water change you are diluting the CL2 by 2.5
x. When the water leaves your tap it is under pressure.
When it reaches the outside world the gasses come of
very quickly. YOu can often see that as tiny bubbles on
the aquarium glass etc... Most of the Cl2 is gone before
it can cause problems. The rest difuses out by it self
in 24 hrs, without being a threat to anything ever...
The only time you need worry about the Cl2 is if you are
refilling the tank or doing more than a 50% water
change. Of course if you have supper sensitive fish you
will have to worry...
Chloramine is a different story. It is more stable,
toxic (to people too!) and soluable. It does not degas
like normal Cl2 and it lasts a lot longer than 24hrs.
Breaking the amino bond frees it to act like usual
except now you have nasty ammonia in the tank... You now
have 3 choices:
1) does with dechlorinator X
2) rely on your plants/bacteria
3) just do smaller water changes.
Fishtanks are a strongly oxidative environment, the
chloramine will degrade faster than it should. Just
doing a smaller untreated water change will see the
chloramine break down over a week or so releasing small
amounts of NH3 and Cl. The free Cl diffuses out and the
NH3 is taken up by plants/bacteria. The plain chloramine
is the problem. at the 3.5 ppm dose stated it is toxic
even after dilution. YOu will have to treat with a
dechlorinator according to its use for chloramines. You
will also have to push up the aeration as there will be
gill damage. Interestingly, if you have 3.5 ppm
chloramine, you only have half the Cl2 you had before as
the chloramine bond is: NH2Cl. The ammonia is the big
problem, but again only if you are doing big water
change or are ill equiped to handle it.
Unfortunately I don't know enough about the organic
chemistry involved to give better answers.:-(
bye
Tyrone Genade
Southern African Killifish Society Coastal & Offshore Coordinator
AKA 08248
tyronegenade at yahoo.com
http://www.geocities.com/tyronegenade
*************************************************************
P450 Lab, Biochemistry Department
University of Stellenbosch, 7602, South Africa
Ph: +27-021-808-5876, fax: +27-021-808-5863
**********************************************************
In God I trust,
but in all others I must have irrefutable proof!