A suitable alternative to distilled water?

[doitmyself]

Wow, these distilled water coolant threads always go overboard, but they are interesting none the less.

Samicar, I agree with your assessment and the basic concepts in your link. Note that your article states that soft water conditioning does NOT change the TDS (Total dissolved solids)of the solution.

My take is that the coolant manufacturers recommend using distilled or other "pure" water, and that's what I do. The difference between RO, DI, and distilled water is moot for coolant use. Softened water is not "pure" and in my local, it pushes the EC meter to outer space. While it may not be corrosive, it also may not create the "best" coolant solution. I don't wish to waste my time pondering if it is good enough. Distilled water is just too cheap.

Everyone forgets how variable tap/well water is across the country. Some is pristine, other is not. We can't generalize about this for everyone.

I also think so many of these discussions are penny wise and pound foolish. People try to save $5 dollars on something you do every several years on something that's valued at $20,000 +/-.

Just my way of thinking and I don't push it on anyone else.

 

[Garak]

Originally Posted By: Samilcar
Water softeners work on a system of ion exchange. They do not work by simply mixing salt with water and serving you this salt water solution to drink. While water softeners do use salt (either Sodium Chloride or Potassium Chloride) in the ion exchange process, this salt IS NOT PRESENT in the treated water that comes out as a finished product. Any Sodium that is present in softened water isn't in the form of Sodium Chloride (salt), but as an elemental Sodium ion.


I know precisely how ion exchange works, and it's not as cut and dried as that. The dissolved minerals that make the water hard in the first place have a greater attraction to the resin media than does salt. That's what allows ion exchange to work. A highly concentrated brine solution is used to flush the resin free of hard water minerals. As hard water passes through the resin, there is ion exchange; hence, the process of ion exchange.

As that proceeds, a very small amount of salt is released back into the water. Anyone who claims otherwise is ignoring conservation of mass - matter can neither be created nor destroyed. When you put twenty pounds of NaCl into your water softener and find it empty sometime later, it obviously went somewhere. Most went out through the brine rinsing, of course. However, not all of it does, simply because the resin cannot become magically virgin clean of salt after the rinse.

Salt goes in - salt comes out. That's simple chemistry at work. It's no different than the use of excess reagent in chemistry experiments. That's the entire principal behind which a salt softener works - excess salt.

You can easily balance equations on paper having a given, exact amount of Na+ or K+ ions replacing another given, exact amount of Mg2+ or Ca2+ ions with no difficulty. Doing it in the lab or in a water softener is, however, another matter.

Whether or not its safe to use in a cooling system is another matter. I'd prefer RO or distilled water, but I'd use soft water over hard water every time. That doesn't mean it's salt free. It's salt concentration may be so low as to be insignificant from the standpoint of cooling system corrosion, but it's not going to be zero.

 

[Samilcar]

Originally Posted By: Garak

a very small amount of salt is released back into the water.


Agreed, but this very small amount is on the scale of parts per billion (assuming a properly working softener).

 

[Samilcar]

Some interesting (but long) reading here from this old thread about allowable levels of salt in ASTM reagent water:


Type III (distillation OR reverse osmosis OR deionization)
maximum allowable salt level - 20,000ppb


Type II (reverse osmosis OR deionization followed by distillation)
maximum allowable salt level - 10,000ppb


Type I (triple distillation followed by deionization) maximum allowable salt level - 2,000ppb

 

[edhackett]

Huh, where did you come up with those numbers? They are wrong.

http://www.chemistry.nmsu.edu/Instrumentation/ASTM_H20.html

Ed

 

[Garak]

I'm not sure if Samilcar's numbers are right or wrong. I don't feel like converting micrograms per litre for sodium or chlorides to parts per billion of salt right now.

Either way, we're agreed that it should be pretty low. I can get virtually an unlimited supply of RO water for next to nothing. The university might frown, however, if I wander in with a a half dozen gallon jugs to fill with Type I water.

 

[edhackett]

Well, the specification is max 1 ppb Cl, so that would be 1.66 ppb NaCl.

Ed

 

[Stelth]

Since I just got back from the radiator shop with a new radiator, hoses, thermostat, and a lot of sludge flushed out of my engine, I'm going with distilled water. I took my 2001 GMC van in because it had a cracked radiator tank. The radiator guy called me and told me that I should really get a new radiator, because this one was plugged so badly that it would still be working at a diminished capacity after rodding. I went down and he showed me one of the tanks that was about 1/3 full of packed residue. So at least the bottom third of the radiator hasn't been circulating water for some time. He said that's what the engine looked like, too.

He also said that that's the result of Dex-Cool plus hard water.

Distilled for me from now on.

 

[Torino]

Just use Mercury. Heat transfer is GREAT. Its a bit dense tho..John--Las Vegas.

 

[Samilcar]

Originally Posted By: edhackett
Huh, where did you come up with those numbers? They are wrong.

http://www.chemistry.nmsu.edu/Instrumentation/ASTM_H20.html

Ed


You are correct, the numbers I posted are wrong. The source I linked to gave allowable limits of sodium and chloride in parts per million when in actuality they are supposed to be parts per billion. Off by a factor of a thousand. Sorry.