"RichToyBox" wrote in message
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"Gill Passman" wrote in message
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BoyPete wrote:


Just why would tap water be saline? It's 'fresh' water.

LOL - I've been dying to ask that question every since I saw the
question of salinity raised in this thread......and BTW I do have a
hydrometer and have checked the tap water (zero of course) but only out
of idle curiousity after checking my marine tanks....

Gill

I have been told the hydrometers just aren't sensitive enough to be able
to measure the salinity of tap water or even our pond water. They are
designed for testing water with salinity of around 3.5%. My pond water
tests at around 0.03 or 0.04% by salinity meter without any salt
additions. When treating for nitrites, the level desired is around 0.1%
to 0.15% which is still a very low level compared to the design of the
hydrometer.

One of the bottled waters that we have bought for drinking is a product
of reverse osmosis or distillation, per the bottle, with sodium chloride
and calcium carbonate added for flavor. G

You can measure the total dissolved solids of freshwater using a
conductivity meter. Here is how to do it:

http://tinyurl.com/rn55l

Note: Total Dissolved Solids=TDS (mg/L) = EC (µS/cm at 25oC) x 0.6

where EC=Electrical conductivity.

George