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Re: NFC: aquarium basics site

>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
>pH=4. My 270ppm tap water, OTOH, is about 200ppm hardness (CaCO3
>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

How am I doing so far? :o)

Is there an easy conversion from microsiemens to ppm?


Brian Perkins, President
Metroserv Incorporated
     Tigard, Oregon