I personally want to know what people find after 4 years of running distilled water. If they find a shiny copper block then I would be very happy to use pure water.
Copper blocks wont be shiny after 1 year or 4 years of either automotive coolant with inhibitors or pure distilled with biocide. There will be some black/blue oxidation from 02, which forms a self protective film on the copper which does not impede performance, as temps same after cleaning it off. But I have had fittings and blocks for that long using distilled and using antifreeze, both look same, both just mild oxidation, both look and work fine.
4 years ago everyone was under the assumption that Copper would ionize distilled water, and back then distilled water was NOT recommended. In fact back then it was highly recommended that you do NOT use distilled water, and that water should be mixed with an anti-corrosive agent (like Anti-Freeze).
Copper and brass both ionize in water, and are eroded very slowly by distilled water, it is a well studied fact known for decades and has even been quantitated by multiple sources in auto and cooler tower industry...it take years to remove even a few microns of copper surface IN A CLOSED LOOP, since distilled after solubilizing copper to 2-3ppm is no longer pure distilled, and its aggressiveness decreases rapidly over time and the oxidation is self protective.
HOWEVER adding ethylene glycol or propylene glycol + corrosion inhibitors slightly increases the erosion, as inhibitors do little to stop ionization of copper in liquids, (they work by coating the anode and preventing interaction/corrosion with the anode), and glycol is slightly more corrosive than distilled water. See chart below and see increase loss with glycol + corrosion inhibitors. (note this is auto fluid, the plain water is distilled). If all that was required to prevent ionization was to use corrosion inhibitors, NASA would not have spent so much money developing nanoparticles to scavenge ions and decrease fluid conductivity over time.
8+ years ago, everyone used antifreeze + distilled because everyone, including me used aluminum in either block or rad, as choices were few,
and aluminum,
unlike copper and brass, is aggressively eroded in distilled/glycol unless corrosion inhibitors are present,
not to mention mixing metals required anti-corrosion. Few had problems with this until jet impingement plates came along, then people started getting crapped up blocks with sludge. We argued back and forth whether it was corrosion inhibitors like silicates (known to cause sludge in automotive industry under certain circumstances) or glycol was being separated with injection plate causing the goo/sludge.
Then out came all copper wb and brass rads. Now, no one needed to use anything but distilled and biocide, and for years the goo/sludge problem was nearly gone (except for those still using auto fluid). PT NUKE (copper sulfate), is in parts per million (0.00008%), and PT PHN (BAK) is concentration of .0003%, ie if either did separate out, you would have a hard time finding that miniscule amount on your waterblock. But I have never seen a loop with plasticizer free tubing, distilled water, and PT nuke/silver/PHN with goo/sludge.
As an aside, one other quote...
The idea was that if we reduce surface tension we can get out water molecules to get closer to the molecules of our heat/cooling surfaces thus improve our performance.
For cars it is debatable, for PC's it is not. In a car, places in engine block can get hot enough to form vapor/gas bubbles in cooling liquid, and gas/air is a poor heat conductor. On automotive sites, people argue whether reducing the surface tension which decreasing vapor bubble formation outweighs the additives decrease of the thermal properties of water. In a pc forum that subject is not relevant, as waterblocks do not get hot enough to form vapor bubbles. And if you want to decrease surface tension enough to decrease vapor bubbles in a system (car) where they exist, a drop of detergent isn't the way.
Bottom line, distilled with biocide PT NUKE/PHN/silver coil and plastisizer free tubing is not going to cause problems by themselves, and you will not see any significant corrosion in life of your blocks, and I go year+ without breaking down, providing your just using copper/brass in your loop or properly plated nickel fittings/etc.
As for feser one, which is distilled water and antifreeze and 4 corrosion inhibitors, been there, done that, it is just expensive antifreeze/water/inhibitors....it is all risk and zero benefit unless mixing metals or using aluminum, which I no longer have to do.
As for dyes causing issues, again, colored tubing is risk free and fades less over time. Dyes just add one more unknown, and maybe it is a reaction with them an something else causing precipitates/goo. While I applaud your curiosity, mine is limited by the unnecessary risk and the the time and energy wasted from having to clean out crap not just from waterblock, but in rad where you cant see, when I have a risk free, tried and true method that has worked for years.
Medical? Heck yeah, few folks like that around here... Engineers in many disciplines.. Well need not ask the others how many haunt here.
