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Re: NFC: aquarium basics site

On Wed, 17 Nov 1999, Brian T. Perkins wrote:

> >
> >My RO (reverse osmosis) water, at 10ppm tds, initially is about pH=8. On
> >standing, that drops a lot, and with some peat, I can easily push it down
> to
> >pH=4. My 270ppm tap water, OTOH, is about 200ppm hardness (CaCO3
> equivalent)
> >so it is difficult to get it down even to neutral without creating a horrid
> >chemical soup.
> Thinking out loud:
> So, TDS is the sum of all the dissolved material in the water (metal
> salts,etc.) that would affect the conductivity of the water as read by the
> meter. The presence or lack of these materials would in turn affect both the
> water's buffering capacity (important to avoid wild pH swings and possible
> increase in ammonia toxicity, etc.) and the Hardness (presence or lack of Ca
> and Mg) So, if an organism has adjusted to a certain level of TDS in their
> water and then is subjected to a sudden change, then Osmotic shock
> (especially across sensitive gill membranes) can occur either killing them
> outright or weakening them to the point where disease organisms can gain a
> foothold.
> How am I doing so far? :o)
Seem to have the gist of it. :)

> Is there an easy conversion from microsiemens to ppm?
Sorry, nope.  (At least not that I know of.)  Depending on what you want
to do, it is possible... but, still, relatively difficult. . . . I use a
chart. :)

> Cheers,
> Brian Perkins, President
> Metroserv Incorporated
>      Tigard, Oregon
Evil List Admin and General Evil Lurker-Klingon Guy.