Re: Death In a New Plant Tank

"Thomas Narten" <narten at VNET_IBM.COM> wrote: 
>> Last Night while doing my weekly 25% water change all 3 of my black mollies
>> died within 12 hours.
>> Should i buy one of those fancy kits for transfering water from the tap?
>> Should i put my water in a barrel for a day to let the Chlroine evaporate?
>This last comment implies that you are not treating your water before
>adding it to your tank.  Do you like living dangerously?
>Although many folks don't bother treating tap water when doing water
>changes, it is a fact that all municipal water has chlorine in it (EPA
>requires this). 

Fortunately, this is not true. We have three water sources in Santa Clara. One 
is San Jose water, required to have chloramines. San Francisco water 
(Hetch-Hetchy) is wonderfully soft, but has chlorine. The center of old Santa 
Clara is on wells, and falls below the threshold requiring chloramines (I 
think it is 500,000 population and above). Barring a major shutdown or 
water-main break that would allow outside sources to be used in an emergency, 
we "never" have any chlorine in our tap water. It's just rock hard at 450 ppm 

>The exact concentration depends on lots of factors and
>can be highly variable over the course of the year.  During the
>summer, for example, chlorine concentrations are generally higher to
>cope with the warmer water temps. If you add enough chlorine to your
>tank during a water change, you will kill your fish.  Even if you
>don't kill them, you are probably stressing them.

I sure agree with this. Overnight doesn't help with chloramines, either, for 
they are both deadly and stable for more than a week. Breaking the 
ammonia-chlorine bond can leave you with toxic levels of ammonia, too, if your 
pH is much above neutral.

The solution is to have a serious conversation with your water dept. 
engineers, and find out what you are dealing with locally. Then get a proper 
product for decontaminating your water, or be prepared to store and air it out 
for a couple of weeks.

>Local fish stores in Durham have recently complained about "bad
>water". I have no sympathy for them.  Sodium thiosulfate is so cheap
>that there is absolutely no reason not to use it. Just because you've
>"never had a problem before" doesn't mean you won't next week.

How much sodium thiosulphate is an appropriate amount to use, and what does it 
do with chloramines? I have photographic sodium thiosulphate on hand, but 
wouldn't know how to use it if we did have that hypothetical emergency. Is 
trial and error, with a chlorine test, the best way?