[time-nuts] Z3816A Control and Cleaning

[Larry McDavid]

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)