I am not a Chemist and I don't pretend to be (though I may play one on TV).
First water is considered a "good" solvent. It will hold, among other things, Iron, copper, Aluminum and allot of components of plastic. It is also great solvent for Oxygen (which causes corrosion).
Now Pure water or Distilled water should be pure (other then Oxygen) in it, but many chemicals will persist through the distillation process if it is not done carefully. The idea is to get all other substances to turn to gas and leave the original water before the water boils. Such substances (like Alchool, Chlorine, most acid's etc) can be removed. When the water boils we then collect that gas until the water evaporates. Continued boiling will result in liquefaction or boiling of other substances.
Boiling water will not kill many bacteria or algae, not to mention that alcohol, chlorine and so many other chemicals will be brought through the distillation process. Granted distillation of water to remove purities is rather efficient, but hardly enough alone to eliminate impurities. Don't beleive Me? Then turn on your video camera, take a nice scoop of sewage, distill it, then drink it...
Now with the idea of solvents. Water is a solvent. It has the capacity to hold X amount of substances. If you add another substance (lets say Y) it will decrease the ability for X to be dissolved. In this example we can say that we will add silver to the water, and that silver will prevent more copper from entering the water. Besides for silver being EXTREMELY TOXIC when dissolved, it may also have other negative side effects to a water cooling system.
Remember Oxygen is almost always present in water, and in our water cooling systems we are almost always introducing more oxygen. Oxygen and Water will corrode Copper where it will start shiny and get more and more darker, and eventually green.
So we can do two things. A) Eliminate the Oxygen by dissolving something else, or B) inhibit the ability of Oxygen too interact with copper (or plastic, rubber's, etc). The Automotive industry, Nuclear Industry, Coal Industry, Chemical Industry, and just about every one wants products and processes that prevent corrosion. Our modern world is full of things breaking down, and we work hard at creating new ways to stop that from working on it. Many people are working hard at making chemicals that make things work better and last longer. Some of these things can be used in our systems. It just takes knowledge, experience, experimentation, and time to get a product that works for OUR needs.
Now we can use these same chemicals in our loops to control how our solution reacts in our system. We can add lubricants to help with pump parts, anti-corrosives to prevent oxidization and dissolving of copter, plastic and rubier, and other stuff. To deny our water loops of these things is to put our heads in the sand and say "Well all is good down here in pure water land!".
The problem is, it takes a person with real understanding and a scientific approach. Looking at reports on the Web is hardly scientific. Many things maybe going wrong in our systems. The components can be breaking down, the plastics and rubbers deteriorating, etc. Some get reported, others do not... and we rarely hear reports that "all is well"...
Now onto surface tension. I know that soap reduces surface tension. Surface tension is most people see on the TOP of water, but in fact it surrounds water. Its the water molecule begin attracted to other water molecules and away from other things (like plastic, rubber and reportedly metals). 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.
I have seen reports with minimum impact regarding surface tension reduction methods. Most successful reports are of substances that reduce surface tension and also provides an additional benefit (like lubrication, anti-bacterial, anti-corrosive, etc), We probably wont noticed the effects of reducing surface tension in our systems.
The tests I depend on are not accounts from user posting in. They are carefully written, carefully carried out studies. The auto industry is a great source for information since they deal with the same problems we do, but they have allot more money to solve the issues.
Corrosion does happen. I am not limiting this to the corrosion of copper but also tubing, paint, copper, rubber, nickle platting etc... These things will form in our loops and we will see the result of them on our cooling systems. The corrosion of copper will reduce its effects to transport heat to the water. Tubes will leave plastic in the water which will gather (among other places) on our copper in our blocks and our rads. We will also see lubricants from pumps, and the inevitable rubber gaskets get corroded.
The MCP655 pump is a rather tough
and will probably not stop if you pump sewage through it. Its the reason we still use it after all this time. It is actually a pump designed for and used in Aquariums.
So we take a solution that has water in it. We run it through a cycle of heating and cooling. We add some electrical charge (to encourage corrosion) and we get a perfect situation to start building "goo", "gunk", "debris". Many of this will be transparent in pure water, or not very visual when we place it against something like a nice copper heat sink. So no one complains, or they simply clean it up on their regular tear down and move on. But if we add Dyes to the liquid, all of this once transparent crud will now become VERY visual, and thus we will point to it and say "ITS THE DYE!". When infarct it is simply colored copper, plastic, lubricants, dust, algae, or anything else that has made it through our system.
The actual amount of Dye used to color your water is relatively small. I have seen small tubes of the stuff. Also, you may get UV reaction to many things. I remember my dorm neighbors drawing on their walls with Laundry Detergents which would appear invisible on white walls, but light up under a black light!
I also see allot of mention about algae, but almost no mention of bacteria. Bacteria is EVERYWHERE. Its found 5 miles down in solid rock, in water that exceeds 320f, and in everything we eat, touch, look at, and breath. Its tough, it multiplies EXTREMELY fast, and it survives and adapts. We treat our water with Anti-Alga's, but do nothing to stop bacteria. Also Bacteria lives in total darkness and is often very transparent (unless you DYE it!).
The main reports of problems almost always occur around the CPU. I dont find this as a surprise since the CPU and the Pump are the two places with a magnetic charge, and the CPU block is the most easily seen and also intentionally has the largest surface area.
Not to mention that some/most dyes do not become gooey under any circumstance. They could also turn into a gas!
I do agree to the fact that plain water and Algae will see little problems, except for the long term corrosion that WILL take place... I also know that these problems will be less visible to most people (and thus less reports on the forums). I do reject the fact that pre-mixed fluids are all snake oils, but will concur that we do not know what is in these mixtures, nor if they do what they claim. That does not mean that there is not a conceded effort to actually create a successful liquid that meets most peoples need.
If your interested run controlled scientific studies. I would suggest having a controlled heat source that can put out a very steady and consistent amount of heat over a controlled amount of time. Also have a controlled cooling environment where the air pressure, air humidity and air temp is controlled. We would also want to control flow rate. Only then can we experiment with things and find out its effects on heat/cooling. After which we can study the results and methods, make changes to the process, and come to a reasonable conclusion. Anything less can not only be untrue, but quite misleading and/or false.
Now you can pick apart this VERY long post. There is allot in it, and I am sure there is allot to add and correct. I am not a chemist, and I am certainly not going to write a white paper on the subject. But what I can conclude is that A) water alone is not the best solution, B) We are all just guessing as too what is the best solution, because few of us have the time or will power too actually follow a scientific processes, and C) that Dyes are visual by nature and thus when a problem does occur, the Dye will do its job and make it MORE visual.
I would love to see this topic talked about in an open and fun way, but I hope people will see this post in its entirety.
