[time-nuts] Z3816A Control and Cleaning

[J. L. Trantham]

Larry,

Thanks for the education.

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Larry McDavid
Sent: Friday, January 24, 2014 12:21 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Z3816A Control and Cleaning

Oops! "RO" is Reverse Osmosis. I incorrectly assumed that was widely known.
I've had an RO system under my kitchen sink for 30 years. Even CostCo sells
RO systems you can install yourself. There is a separate spigot faucet on
the sink for this mineral-free water.

RO systems first pass city water through a fine particle filter, then allow
only pure water to pass through an osmotic membrane into a low-pressure
storage tank. Before delivery out the separate spigot, that RO water is
passed through an activated carbon filter. All this hardware resides on a
smallish vertical platform under your kitchen sink.

Here in Anaheim, California, where all water is imported directly or
indirectly, the mineral content is relatively high. I maintain my RO system
carefully and monitor how it performs by measuring the water conductivity,
which is commonly referred to in water reports as Dissolved Solids in ppm
(parts per million).

My city tap water measures between 600 and 800 ppm dissolved solids (and,
sometimes higher); my RO system delivers water at 8-12 ppm. True distilled
water will measure 0-2 ppm dissolved solids so RO is almost as good, good
enough to not make a difference for our purposes, except perhaps in the
highest imaginable high-impedance or high-voltage circuits.

So, what is it that causes the high dissolved solids content of tap water?
It is *salt* in one form or another, generally magnesium and calcium salts,
and can include common sodium chloride (table salt). Salt is electrically
conductive so measuring water conductivity is a common way to evaluate
mineral content. Many years ago a company named Myron-L established and made
popular an assumed mixture of salts found in tap water and "calibrated"
water conductivity in "dissolved solids." This assumed mixture and reporting
in dissolved solids remains popular today. 
You likely get a water purity report from your local water supplier; look in
there and you will find dissolved solids reported in ppm. You may also find
specific minerals reported but that is not done by conductivity. Sometimes
you see conductivity reported as conductivity (reciprocal of resistance),
with no attempt to convert to a dissolved solids percentage.

Think of taking a 5 gallon jug of distilled water and adding a teaspoon of
table salt. Would you want to drench your electronics with that water?
You'll never get all the water blown out or drained out; what water remains
will evaporate. What remains after evaporation is the minerals or salt. Not
good to have salt on your circuit boards!

It is difficult to harm any electronics by drenching them with distilled or
RO water. What does not immediately drain out simply evaporates over time
but leaves behind no mineral salt and causes no problem.

Drop your cell phone into a lake? Immediately soak it in distilled water to
dilute the salt in the lake water. Spill coffee on your keyboard? 
Drench it with distilled water and let it dry. Let anything you get wet, dry
thoroughly before re-applying power! Use slightly elevated temperature to
accelerate evaporation.

Ever wonder what causes "water spots" on glassware you don't dry with a
towel? Those spots are simply mineral salts left when the city tap water
evaporates. I often hand wash a few dishes in my kitchen, but then I rinse
them with RO water from the convenient sink-top spigot and let them drain
dry. Guess what? No water spots because there are no significant minerals in
the RO water.

Some homes have "soft" or deionized water provided by a de-mineralizer that
uses salt. The result varies widely and this so-called soft water is not
mineral-free. Some will use this water for electronic cleaning; I will not
and instead use my RO water, which I monitor and know how mineral-free it
really is.

Want to check your own tap water for dissolved solids? Easy and cheap today.
Search eBay for "Dissolved Solids Meter" and you will find many hand-held,
battery powered LCD meters offered for about $10-$12.

RO water is convenient and has other uses around the home. We recently
suffered a period of very low relative humidity (5%) and I started using an
ultrasonic nebulizer humidifier in my bedroom. I fill it with RO water from
my kitchen sink and as a result have no mineral powder falling out of the
humidified fog. Do any metal finishing at home? I always use only RO water
to avoid unexpected results from tap water.

Do you enjoy hot tea? Tanic acid in tea is a mineral indicator and tea made
with "hard" water will be very dark in color. Use RO water and the tea will
be amber and taste better. Same with coffee... My RO system gets a lot use!

Larry


On 1/24/2014 9:12 AM, J. L. Trantham wrote:
> Larry,
>
> Thanks for the info.  What is 'RO'?  I am not familiar with that 
> abbreviation.
>
> Joe
...

--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)
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