"Dominic T." writes:

On Aug 1, 10:09*am, Lewis Perin wrote:
He said both samples were filtered, though.

/Lew
---
Lew Perin /

Yes, but there is chlorine and there is also chloramine which is often
used (chlorine and ammonia so it is more stable and doesn't aerate out
of treated water quickly) Most tap filters remove most of the *taste*
of chlorine but not all of the actual chlorine, so filtering and then
letting it sit will always remove more of it than just filtering or
just sitting. If it is treated with cholramine then tap filters do
less of a job of removing it.

Thanks for the info. I wonder if anyone has reliable numbers on
filtration of chloramine and how fast it'll dissipate in water. A
little Googling found a site that said chloramine in water basically
won't dissipate at all, but it was definitely an anti-chloramine
advocacy site.

Tap/pitcher/etc. filters are also highly variable in quality to begin
with and then you add on to it the flow rate, when it was last
changed, and on and on... so filtering often is doing less than most
would like to think.

Right, the details matter with filtering (and water in general.)

/Lew
---
Lew Perin /
http://www.panix.com/~perin/babelcarp.html

On Aug 1, 2:06 pm, Lewis Perin wrote:
"Dominic T." writes:
On Aug 1, 10:09 am, Lewis Perin wrote:
He said both samples were filtered, though.

/Lew
---
Lew Perin /

Yes, but there is chlorine and there is also chloramine which is often
used (chlorine and ammonia so it is more stable and doesn't aerate out
of treated water quickly) Most tap filters remove most of the *taste*
of chlorine but not all of the actual chlorine, so filtering and then
letting it sit will always remove more of it than just filtering or
just sitting. If it is treated with cholramine then tap filters do
less of a job of removing it.

Thanks for the info. I wonder if anyone has reliable numbers on
filtration of chloramine and how fast it'll dissipate in water. A
little Googling found a site that said chloramine in water basically
won't dissipate at all, but it was definitely an anti-chloramine
advocacy site.

Tap/pitcher/etc. filters are also highly variable in quality to begin
with and then you add on to it the flow rate, when it was last
changed, and on and on... so filtering often is doing less than most
would like to think.

Right, the details matter with filtering (and water in general.)

/Lew
---
Lew Perin /

Yeah I could have better explained myself in my first reply, sorry...
I blame it on the jet lag I'm no expert on chloramine, the only
reason I even knew of it is because I've heard a bunch of warnings for
aquarium water if you live somewhere that does use it. It is used in
large cities, so NYC may use it. I'm sure it will leech out eventually
but how long, I have no clue. I'd say normal chlorine can be
noticeably dissipated in anywhere from a couple hours to a day
especially if it is poured vigorously initially or aerated in some
way. I fill my pond by keeping the hose way up high and letting it hit
hard so that it aerates as it fills instead of laying the hose in and
letting it fill.

From what I've seen as far as making aquarium water safe is chlorine
tap water needs 1-2 days, and chloramine needs a week. Again, how true
or scientific this is I have no idea. And aeration speeds it up, so in
theory simply boiling the water and letting it boil a short while
would also eliminate chlorine.

- Dominic