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RoboTech · 07-19-2003, 08:00 AM

Hey Ben,

Yes, I understand that DI and distilled are not the same...

My point was that too often I hear the general statement made that "DI water is bad for you, some even go so far as to claim poisonous, and that you should not drink it". Now I'm NOT suggesting that anyone should go out and start drinking DI water... but on the other hand if you were to drink a glass full, it wouldn't hurt you either. I think the key to Alchemy's statement is "in large quantities".

I am somewhat familiar with water purification. One of my responsibilities at the facillity where I work is maintaining some of the water purification systems (when I'm not programming robots). This is a pic of a typical industrial pure water system (semiconductor plant, etc.).

City water > chlorine scrubber > water softner > RO filters > DI resin bed > UV light bank > Ozone addition. It generates pretty good high quality water (~15 Meg Ohm).

If that's not good enough for the end users (analytical labs) they run it thru point of use bench top finishing units.

Here it goes thru several more resin bed DI and activated charcoal filters, UV light, another DI resin bed and membrane filter => ultra-pure water. Water conductivity measured with a flow cell is about 18.2 Meg Ohms but by the time it hits the air and sits in a glass beaker long enough to take a conductivity reading its already picked up enough ions to be down around 1 Meg Ohm.

I agree with your statement about distilled water (as long as it's steam distilled and not vacuum) - steam distillation is pretty good at killing and removing biologics but salts are generally NOT carried over. Distillation is considered one of the best purification methods but it is expensive (energy input) and will not remove other volatile contaminates with a similar or lower boiling point as water!

DI water is completely stripped of "ions" true, but that doesn't mean that it can't contain impurities and contamination. A DI filter (resin exchange bed) will only remove charged particles, everything else will pass thru unless it is physically held back due to particle size.

Edit: The "best" water purification systems use multi-phase purification (physical filtration, absorbtion-charcoal, RO, DI and distillation) as each has its own strengths and weaknesses. Put them all together and you should get pretty good water...

Again... IMHO one of the best sources for PC water coolant is the grocery store - look for a brand of distilled water that has been RO (reverse osmossis) filtered, steam distilled and ozonated. Man, all this talk about water is makin' me thirsty...

07-19-2003, 08:00 AM	#7
RoboTech Cooling Savant Join Date: Sep 2002 Location: Cincinnati, OH Posts: 229	Hey Ben, Yes, I understand that DI and distilled are not the same... My point was that too often I hear the general statement made that "DI water is bad for you, some even go so far as to claim poisonous, and that you should not drink it". Now I'm NOT suggesting that anyone should go out and start drinking DI water... but on the other hand if you were to drink a glass full, it wouldn't hurt you either. I think the key to Alchemy's statement is "in large quantities". I am somewhat familiar with water purification. One of my responsibilities at the facillity where I work is maintaining some of the water purification systems (when I'm not programming robots). This is a pic of a typical industrial pure water system (semiconductor plant, etc.). City water > chlorine scrubber > water softner > RO filters > DI resin bed > UV light bank > Ozone addition. It generates pretty good high quality water (~15 Meg Ohm). If that's not good enough for the end users (analytical labs) they run it thru point of use bench top finishing units. Here it goes thru several more resin bed DI and activated charcoal filters, UV light, another DI resin bed and membrane filter => ultra-pure water. Water conductivity measured with a flow cell is about 18.2 Meg Ohms but by the time it hits the air and sits in a glass beaker long enough to take a conductivity reading its already picked up enough ions to be down around 1 Meg Ohm. I agree with your statement about distilled water (as long as it's steam distilled and not vacuum) - steam distillation is pretty good at killing and removing biologics but salts are generally NOT carried over. Distillation is considered one of the best purification methods but it is expensive (energy input) and will not remove other volatile contaminates with a similar or lower boiling point as water! DI water is completely stripped of "ions" true, but that doesn't mean that it can't contain impurities and contamination. A DI filter (resin exchange bed) will only remove charged particles, everything else will pass thru unless it is physically held back due to particle size. Edit: The "best" water purification systems use multi-phase purification (physical filtration, absorbtion-charcoal, RO, DI and distillation) as each has its own strengths and weaknesses. Put them all together and you should get pretty good water... Again... IMHO one of the best sources for PC water coolant is the grocery store - look for a brand of distilled water that has been RO (reverse osmossis) filtered, steam distilled and ozonated. Man, all this talk about water is makin' me thirsty... Last edited by RoboTech; 07-19-2003 at 02:26 PM.