At 11:29 31-08-01 +0200, Tyrone wrote:
>On 29 Aug 2001, at 9:08, bowluvr wrote:
>
> > 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.
Based on health considerations, the Australian guideline value for chlorine=
=20
in drinking water is 5.0 mg/L. The free chlorine residual in major=20
Australian reticulated supplies ranges from 0.1 mg/L to 4.0 mg/ L, with=20
typical concentrations of about 0.2 mg/L, but they will sometimes flush the=
=20
system with higher concentrations.
When ammonia is added to chlorinated water it can produce monochloramine=20
(NH2Cl), dichloramine (NHCl2), or trichloramine (nitrogen trichloride,=20
NCl3). The type of chloramine depends on the pH and the chlorine-to-ammonia=
=20
ratio. At the less corrosive pH of most municipal water supplies (>7 pH),=20
monochloramine usually is formed. Trichloramine exists at a pH of around 4=
=20
with high chlorine-to-ammonia ratios. Dichloramine exists at a pH range of=
=20
about 4.5 to 6 with moderate chlorine-to-ammonia ratios. Monochloramine is=
=20
the best biocide of the three types, but all chloramines disinfect more=20
slowly than chlorine.
Chloramines are formed when chlorine and ammonia are added to water:
NH3 + HOCl > NH2Cl + H2O =3D monochloramine
NH2Cl + HOCl > NHCl2 + H2O =3D dichloramine
NHCl2 + HOCl > NCl3 + H2O =3D nitrogen trichloride (trichloramine)
Dichloramine is a stronger disinfectant than monochloramine but is less=20
stable and has a distinct disagreeable odour. Nitrogen trichloramine has an=
=20
extremely offensive odour, and is readily destroyed by sunlight. Low pH and=
=20
a high ratio of chlorine to ammonia favour the formation of the less stable=
=20
chloramines, so the ratio is controlled at levels of 3:1 to 5:1 to ensure=20
that monochloramine is the major chemical formed at normal pH levels=20
(7.5-8.0). Monochloramine is a weak disinfectant, requiring 25 to 100=20
times the contact period of free chlorine for equivalent disinfection;=20
however chloramine persists in distribution systems and continues to=20
disinfect in the extremities of large systems.
The actual toxicity of chlorine/chloramine depends on the fish species,=20
water temperature and dissolved organic carbon levels. For example, at 5=B0C=
.=20
Koi can die from just 0.2 or 0.3 mg/L of chlorine after several hours. It=20
may take 10 times that amount at higher temperatures or in waters with a=20
high level of dissolved organic waste. Many fish exhibit serious stress=20
signs at 0.01 mg/L, and death can occur anywhere in the range of 0.005 to=20
5.0 mg/L. Larger fish usually die more quickly than smaller ones and at a=20
lower ppm. Even minute quantities of chlorine can severely damage the=20
bacteria in your biofilter system. Often times, the disruption of the=20
biofilter (and the resulting ammonia/nitrite spike) following the initial=20
damage to the fish is what causes them to die 3 or 5 days after the=20
chlorine event.
The difference in price between a standard chlorine neutraliser and a=20
chloramine neutraliser is not worth worrying about so why use a standard=20
chlorine neutraliser?
Why put your fish through the stress of possible death or gill damage. Most=
=20
of you will have fish worth more than a bottle of chloramine remover.
It just doesn't make sense to me ???????
Adrian.
Adrian R.=20
Tappin
Home of the Rainbowfish
http://members.optushome.com.au/chelmon
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At 11:29 31-08-01 +0200, Tyrone wrote:
On 29 Aug 2001, at 9:08, bowluvr wrote:
> Gary's argument was simple: active, funtioning bio and/or=20 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=20 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.
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