Login to ProCooling
Name: Pass:
Not Logged In.
ProCooling Technical Discussions
Getting back into the water
ben333 7 Day(s) ago.
ID This Waterblock.
jaydee 469 Day(s) ago.
Long Shot: Looking got an old radiator(heater core...
Sled_Dog 676 Day(s) ago.
Old Watercooler Returns to Custom Loops
Sled_Dog 683 Day(s) ago.
ProCooling Geek Bits
Fluke 17B+ ... the multimeter I've always wanted b...
Noise 776 Day(s) ago.
Ben's Win 98 box, redone! Build up
ben333 2431 Day(s) ago.
Project Black & Blue - Ben's new HTPC
ben333 2491 Day(s) ago.
Bring back IRC?
ben333 3286 Day(s) ago.
Site News and Blogs
User Registrations kinda back open
ben333 7 Day(s) ago.
New User Registrations are blocked
ben333 7 Day(s) ago.
Where is Joe these days? JoeKelly.co
ben333 297 Day(s) ago.
Stuff over the last few years, Blogs, etc...
rhkcommander 681 Day(s) ago.
The Pro/Market
GTX 280 for US $308.11 !!!!!!
sam amaar 1154 Day(s) ago.
FS: Laptop hardware (CPUs, Memory, HDDs, Wifi, etc...
ben333 3292 Day(s) ago.
FS external watercooling units from jpiperformance...
Halo_Master 3331 Day(s) ago.
FS Snap Server 4200
abuthemagician 3456 Day(s) ago.
The The Chemicals OC'n and Super Cooling - Coolants
Date Posted: Sep 16 2002
Author: Brians256
Posting Type: Article
Category: H2O and Evap
Page: 2 of 2
Article Rank:5 from 1 Readers
Must Log In to Rank This Article
Note: This is a legacy article, imported from old code. Due to this some items on the page may not function as expected. Links, Colors, and some images may not be set correctly.
The Chemicals OC'n and Super Cooling - Coolants By: Brians256

The Chemicals of OC'n and Super Cooling - Coolants

By: Brian 9/16/02

Page 2

Biological Growths

Nobody wants things growing in their computer. Biological growths can cause the hoses to become clouded or even turn different colors. The best way to prevent the growths is a combination of methods. First, use distilled water to avoid adding algae and other life forms from the start. Then, add some biocide to prevent life from migrating in and finding a good spot to grow.

This problem has seen some of the most interesting additives put into computer cooling systems.  People have put mouthwash, dishwashing soap, pool chlorine, and many other strange substances into their computer coolants to kill existing growths or prevent future growths.  Unfortunately, a minty-fresh smelling coolant does not guarantee that it has no algae.

Most of the chlorine additives are effective at killing germs and algae, but chlorine quickly evaporates from water. So, bleach will work for a short time, but it is only temporary. Also, chlorine is a very reactive substance that causes gaskets and some types of tubing to become brittle.  Be wary of adding a cup of bleach to your coolant.  It may cause your pump to start leaking!  If you choose this route, add a teaspoon to your loop every month, and carefully monitor the pump and tubing for leaks.  Bleach may also be corrosive to metals in your system (it is a powerful oxidizer). Dishwasher detergent does contain some chlorine, which is probably why dishes come out so sparkling and clean. So, you could add detergent, but it also causes a problem with foaming (i.e. try something else).

Alcohol is similar to chlorine biocides but not as harsh.  For a given concentration, it kills less effectively than chlorine, but it is also easier on gasket materials (as far as I know). Unfortunately, it will also evaporate from the coolant although not as quickly as chlorine.  A good idea would be to add a teaspoon or two to your coolant and change the coolant every 3 to 6 months to refresh the biocide.

Neither Water Wetter™ nor antifreeze is a good biocide.  However, they do provide higher pH (base instead of acid) so that some growths do not form as readily.  The majority of bacteria prefer to live in a slightly acidic environment. Many people with closed loops run distilled water and Water Wetter™ for long periods of time without any biological problems.


Notes for Controlling Biological Growths


Decent biocide, but will evaporate, may cause seals to degrade, and it does stink. Used alone, methanol is a fire hazard. Requires periodic replacement because of evaporation.

Isopropynol or other alcohols

Decent biocide, but will evaporate, may cause seals to degrade, and it does stink. Requires periodic replacement because of evaporation.

Antifreeze (Ethylene Glycol or Propylene Glycol)

I do not know if antifreeze has any benefit in controlling biological growths.


Some soaps have anti-bacterial agents added or even a broad-spectrum biocide such as a chlorine compound. Dishwasher soap probably has one of the highest chlorine concentrations but it does not dissolve well below 130°F.


Bleach is one of the most effective biocides, but it is corrosive at high concentrations.

Humidifier additives


Water Wetter™

Water Wetter™ and its clones have additives to increase the pH to make it more basic (see skin effect above). It is unknown if it degrades, but it is still recommended to change the coolant every six months.

As a last resort, adding humidifier additives or other common biocides such as silver or sodium azide can help.  Some people recommend biocides from your local pool supply store, but those are very powerful chemicals. In other words, be careful with any of these chemicals! Read the labels and add only the required amounts, because more is not necessarily better.

Precipitated Solids

Precipitated solids are a related effect to galvanic corrosion in that dissolved metal ions get dumped out of solution onto a ready surface. However, the most common precipitated solids arise from ions present in a poorly chosen coolant: calcium carbonate (CaCO3) and magnesium carbonate (MgCO3). Typically the problem starts when someone uses tap water instead of distilled or de-ionized water.

The composition of tap water is varied, but it will typically contain fairly high concentrations of Ca2+ and Mg2+ (dissolved Calcium and Magnesium). Some tap water even contains copper and lead, which are not particularly good for your health. When these ions are placed into a cooling loop with dissolved CO2 and Water Wetter™, then eventually solid phases (CaCO3 and/or MgCO3) will start to precipitate out. Avoid tap water! Buying distilled water is well worth the investment of $0.79 for a gallon. Even a cheap Brita water filter removes the majority of these dangerous (for your coolant) ions.  A water block covered in Calcium Carbonate does not transfer heat nearly as well as a clean block, and when tubing clogs with solids water circulation will suffer.

Heat Movement

The whole point of using water is to increase the amount of heat moving away from your CPU, Northbridge or other hot component. All of the additives we have discussed actually move heat less efficiently than water. But, wait! I hear many people complaining already. Isn't Water Wetter™ good at helping the system work more efficiently?  What about Antifreeze?

Water Wetter™ appears to be mostly a surfactant with a pH alteration to help reduce corrosion.   The surfactant, as we all know, is designed to reduce surface tension. So, it reduces the size of the bubbles that form in a normal car or motorcycle engine as the water boils.  As a side effect, lowering surface tension improves heat transfer at lower temperatures by changing the surface tension and viscosity of water. This results in a more perfect wetting of the surface (contact angle close to 0) which helps the water move faster near the heat exchange surface.  We are mostly concerned about the side effect, as most of our chips do not exceed 212ºF/100ºC to cause water boiling, I hope!

However, pure Water Wetter™ is not particularly good at moving heat. So, if you add too much to your coolant, the total heat transfer efficiency drops. You only need as much Water Wetter™ as it takes to reduce the surface tension.  Any more, and you only dilute the excellent heat moving characteristics of water.  Redline Oil has a page specifically for the Water Wetter™ product, and it clearly shows how adding too much can decrease performance.

Please note that I am using Water Wetter™ as a specific example of many fine products which perform very similarly, such as Purple Ice. Technically, you could use some proportion of surfactant (e.g. soap or glycerin), soluble silicate, and a basic substance (e.g. sodium carbonate or some other substance to increase the pH level). However, it seems more trouble than it's worth unless you plan on using gallons and gallons of it.

I could bring up a table of the heat capacity and conductivity of the other additives, but this has been well discussed in other articles and forum threads. Simply put, pure water is the best at moving heat if you are measuring a static system. If you are using a chiller to go below ambient, consider methanol as an additive to reduce the freezing temperature not Antifreeze. Antifreeze is very thick at low temperatures.  At normal temperatures, the only performance known enhancement is a surfactant such as Water Wetter™ or soap.  However, remember that pure methanol is poisonous and flammable. Silicone tubing may allow methanol fumes to migrate out and reach unpleasant concentrations in a poorly ventilated room.


Notes for Heat Movement


Reduces heat movement efficiency but lowers the freezing temperature. When going below the normal freezing temperature of water, this is the best additive. Note: pure methanol is POISONOUS and FLAMMABLE.

Isopropynol or other alcohols

Reduces heat movement efficiency but lowers the freezing temperature. When going below the normal freezing temperature of water, this is the second best additive.

Antifreeze (Ethylene Glycol or Propylene Glycol)

Reduces heat movement efficiency but lowers the freezing temperature. When going cold, antifreeze substances become very thick and thus reduce coolant velocity.


Reduces surface tension and increases heat transfer efficiency because of reduced skin effect.  Best ratio of water to soap is unknown.


No known effect.

Humidifier additives

No known effect.

Water Wetter™

Reduces surface tension and increases heat transfer efficiency because of reduced skin effect.


First, change your coolant regularly.  All additives reduce in effectiveness as they age   I recommend changing your coolant at least every year or two to prevent scale buildup, biological growths and corrosion problems.

Second, use the required amount of additives and no more!  Remember that more is not better. Adding too much of anything to your water will reduce the effectiveness of heat transfer and it might cause extra problems (e.g. too much bleach may corrode your gaskets).

Third, use distilled water as your base. Tap water has deposits that will clog up your system, cloud up your tubing and generally facilitate corrosion. It also has a healthy starter colony of life-forms waiting to grow in your system.

My recommendation for normal water cooling is to use a combination of Water Wetter™ (or one of its many clones such as Purple Ice) with distilled water (see the product for the recommended mixing ratio) and then change the coolant every 3-6 months. If you are concerned about biological growths, add some methanol or one of the biocides sold by humidifier companies.  If you hate the residue that Water Wetter™ leaves in your silicone tubing, you might try using antifreeze (realizing that you will have a minor performance hit).  If you run a chiller, change that to mixture to distilled water and methanol. Methanol has the lowest viscosity and thermal transfer characteristics of the additives to reduce freezing temperature.

If you are looking for more instant info on this and other cooling stuff, Please visit us in the
or the Pro/Forums

Articles Home

Reviews Home

If you have any comments or Questions please email me at Brian@ProCooling.com

Random Forum Pic
Random Forum Pic
From Thread:
Outrage: cooling 10 comps with an Uber pump and a bong
ProCooling Poll:
So why the hell not?
I agree! 65%
What? 18%
Hell NO! 0%
Worst Poll Ever. 18%
Total Votes:17
Please Login to Vote!

(C) ProCooling.com 2005 - All this glorious web geekness was brought to you by Joe's amateur web coding skills.
If we in some way offend you, insult you or your people, screw your mom, beat up your dad, or poop on your porch... we're sorry... we were probably really drunk...
Oh and dont steal our content bitches! Don't give us a reason to pee in your open car window this summer...