Water Cooling

A Beginner's Guide to Water-cooling
by Phreejak
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Chapter 1: Introduction to Water Cooling
Chapter 2: The Equipment

CHAPTER 1: Introduction to Water Cooling

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Section 1 Introduction

The steady advancement of computers and their components gave rise to the increase in their energy consumption and, consequently, the rise in their internal temperatures due to the collective heat. It became apparent that cooling a computer was a priority and, as the state of cooling concepts were at the time; air was the medium through which the ends would be achieved. Advancements in heat sink and fan design proved usual for a period of time but the technology began to outpace air’s cooling capabilities and further alternatives were needed. The experimentation into water cooling proved successful and its potential as a viable cooling option was born.

Initially, skepticism of such a method of cooling limited its widespread acceptance. Running water through a device that was largely powered by electricity seemed ludicrous at best. However, as development in this area grew, innovation paved the way for the creation of more secure water cooling elements and thus, its acceptance and even its implementation became more widespread.

Now, water cooling has carved itself a niche in system cooling circles and continues to grow in use everyday. There was a time when a person might rarely encounter a water cooled computer. Today, its presence is fast becoming commonplace – both as a method of cooling and as a topic of discussion amongst many enthusiasts.

What this water cooling guide is going to attempt to do is give the new user a better understanding as to what the whole water cooling scenario is about – the philosophy, equipment, effort and expense involved - to better prepare them should they decide to step up to this method of component cooling.

Section 2 Why?

I think the first thing you have to ask yourself is why you want to get into water cooling. When immersing yourself into new concepts and ideas, there are certain expenses involved that could be from the relatively inexpensive premade kits to the more expensive Do-It-Yourself (Hereafter referred to as DIY) projects. Make certain that what you wish to achieve is beyond the realm of air cooling as the potential cost involved is going to be substantially greater. There are some very good heatsink/fan combos that are very effective and, as long as you have an adequate air stream moving through your case, it could be adequate for your needs. The best air cooling solution will perform as effective as some of the cheaper water cooling solutions. That being said, air cooling is much cheaper and is effective - to a certain point.

The Word: Investing in a custom liquid cooling solution for your computer will require that you do some research because you will need to develop your own philosophy as far as how you want to approach water cooling. The information that you collect from the forums and from people who are experienced with WC is a valuable tool. People who have experience with water cooling can help you avoid some of the mistakes you may be prone to make as a newcomer to this field. It’s not enough to know what equipment is involved or how something looks – experience will teach you things that you can’t find out from a catalogue or an online site like how a GPU water blocks construction can affect water flow or determining whether placing a radiator internally or externally is condusive to what you want your cooling loop to achieve.

Don’t be afraid to ask questions, that is what forums are there for – to spread knowledge. For every knee jerk reaction you get from some smart mouth user, there are half a dozen (or more) people who will be more than happy to assist you.

Section 3 Different Classes of Water Cooling

The magical number is ambient temperature.

That is, the ambient temperature (or the surrounding environmental temperature around the computer) is what air cooling and water cooling concepts strive to reach. Neither will attain it specifically but, the allure of water cooling is that it comes much closer than air cooling to achieving this.. Your computer components (those which need cooling) will always be warmer than the ambient temperature. Both use the ambient air around (or in) the computer to accomplish certain results when trying to remove heat from a source. Water cooling is more effective as water is a better conductive medium for removing heat away from a source than air cooling. This is a qualified statement as water cooling is also influenced by the equipment involved.

There are premade kits which are designed to have most of the necessary equipment involved in an effective cooling loop. This is further enhanced by those kits that add additional components to cool your GPU (video card) and Northbridge chipset as well as your CPU. You’ll find kits like the Corsair COOL Water, Thermaltake BigWater, Vantec, Cooler Master Aquagate and Gigabyte among others. These kits come with everything involved in a typical cooling loop – radiators, reservoirs, tubing, water blocks (some include more than just for the CPU), etc. The expense is nominal insofar as typical water cooling kits are to cost. However; with some of these kits, their effectiveness is very limited. Typically, these types of kits will cost no more than $150 with many less than $100.

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The next step, beyond these kits, are the kits offered with water cooling manufacturer’s parts (often offered BY the manufacturers themselves). These kits are considerably more expensive than the aforementioned premade kits in that they involve actual specialized components of a more refined nature. Here you will become more acquainted with the more reputable component companies like Swiftech, Danger Den, Alphacool, Aqua Computers, etc. These kits will normally involve parts made only from the manufacturer for each phase of water cooling – take a typical Danger Den kit – Black Ice radiators, maze 4 water blocks, a Danger Den pump and a Danger Den reservoir – I think you get the idea here. These kits will be more effective than the premade kits previously mentioned as their selective components were designed to be more effective. These kits are offered in many different configurations to cool just the CPU or go so far as cooling the CPU, GPU and the Northbridge chipset. Of course, the price here is considerably more expensive than the premade kits and can be anywhere from $175 to more than $300.

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The last and final step for water cooling enthusiasts is going to be what is often referred to as Do-It-Yourself (or DIY). Here concepts and standard practices are pretty much just used as guidelines as parts are mixed and matched and typical practices are often disregarded for more imaginative solutions. But, be forewarned, this often ends up with considerable expense at its ultimate end. The nice thing about this type of class is that the parts do travel with each computers upgrading and, with the exception of the liquid coolant and, perhaps, tubing, most of your parts will continue to provide you with usage for years to come – regardless of what new equipment comes out. (Of course, there is the change in GPU structure or CPU socket that will necessitate new parts being bought but this is the price of maintaining an absolutely effective cooling solution). Water cooling in this area is often becomes an enjoyable experience because of the reward of designing a working cooling solution takes on a matter of pride. The expense of being in this class is nothing short of a google to the nth power (or whatever that is) but you get the idea – it’s enough to make you pass a bowling ball through your colon.

Section 4 Philosophy

While this is not a really important section I thought to mention that the water cooling enthusiasts here in the United States seem to be more subscribed to a slightly different philosophy than is elsewhere (especially in Europe). Here, while we will use kits that use ¼ ID and 3/8 ID parts and tubing, we have a fondness for ½ ID products and the high flow characteristics and powerful pumps that it involves. I’ve found that most European countries are more apt to use just the ¼ ID and 3/8 ID parts as most European companies that produce water cooling equipment do so for those two measurements. Very rarely will you find much of any European part for larger diameter usage while here in the States it is attainable in abundance.

When planning a cooling solution you will find that your preferences may change over time. Whether you want to maintain a maximumized flowrate and try to limit the number (and type) of waterblocks OR you want to cool as many components as possible, the choice of what to do will be influenced as you gain more knowledge so keep up with the technology!

CHAPTER 2: The Equipment

There is so much that could be mentioned here. I mean, there is so much varied equipment for each section of water cooling that it would take a lifetime to mention them all – so we won’t. We’ll cover the basics of equipment, give a few examples and just hope that it gives you a more thorough understanding of what basically is needed to form a complete cooling solution. Note: the equipment discussed is not to be viewed as any kind of "recommended buyers guide" but was used for purposes of ease of discussion and as examples.

Inner Diameter

There is a common characteristic of water cooling that covers the equipment that you will encounter - Inner Diameter.

It affects everything from the water blocks and radiators to the clamps, tubing and reservoirs. It is the measurement of the size of the inside of the specific type of medium vehicle (i.e. tubing) or connector through which the liquid coolant will flow. When reading or hearing someone speak of something such as "Swiftech Storm Water block with 3/8 fittings" or "reservoir with 3/8 barbs" this means that the equipment is ideally designed to use 3/8 inch tubing. Likewise if your radiator uses 1/2 ID high flow fittings" the only important thing you need to look at is that it said "1/2 ID" which will indicate that it was designed for 1/2 ID tubing. The most common measurements for tubing and connectors are: 1/4, 3/8 and 1/2. You may also see mention of an O.D. or "Outer Diameter". This, of course, is the measurement of the outer wall of whatever component is being discussed. This can vary depending on the type of equipment but is most commonly associated with tubing. A product, as in this case - tubing, can have an ID (Inner Diameter) of 1/2 but can have various outer diameter degrees like 3/4, 11/16, etc. In this case it just helps to distinguish between the different types of tubing products offered for the 1/2 ID product.

When dealing with components like barbs, connectors or fittings you might see them referred to by their "Outer Diameter" Remember, the O.D. is a measurement of the outer wall of whatever component is being discussed. But, it also determines what type of part you may select for use with a particular tubing size. If you have a 1/2 "Inner Diameter" tube then you would want to use a connector, barb or fitting that would fit snugly inside of it. That would mean you would want a part with a 1/2 O.D. I know this can get confusing but it does make sense. For 3/8 I.D. tubing you couldn't use a 1/2 OD barb because it's too big. Likewise, a 1/4 O.D. fitting would be too small. You get the idea? 3/8 ID tubing fits over a 3/8 O.D, 1/2 ID tubing would work with a 1/2 OD connector.

Section 1 Listing

Water block(s)

Section 2 Water block(s)

A water block is, basically, a housing through which water flows to remove heat from a source - in terms of water cooling, a specifically designed mechanism for a specific computer component. It’s the most recognizable part of a water cooling solution because, unlike most other parts, it evolves more often as certain computer parts evolve (like the GPU or a new CPU socket type). The design of a radiator or reservoir rarely ever changes except through conceptual design but water blocks change often based upon need. Rather, it should be said that additional water blocks are introduced into the market as computer parts change so they are the most abundant of parts, ultimately. This is, of course, a generalized statement as some specific water blocks are more difficult to obtain than others. They are all offered with ½, 3/8 and/or ¼ connectors. Not all water blocks offer compatibility with all sizes of ID though – some are designed more specifically to function at particular ID sizes. This listing is meant more as an explanation of the different types of water blocks available.

1) CPU Water block

The CPU block is one of the most important parts of the loop. This is the gateway where the water cools down the CPU. Obviously the block goes on top of the CPU so that there is optimal heat transfer. This might sound like a simple idea, but the world of block design is crazy and very complicated. Like the standard heatsink/Fan combo this also uses some form of thermal paste as an interface between the CPU and the water block.

To uncomplicated things, we’ll classify two forms of CPU blocks.

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Non-Impingement Blocks: these blocks are less restrictive; most of these designs are simple. The water basically flows from one end of the block to another with the addition of some fins which cause turbulence (more water movement = more heat displacement). These blocks are great for people with weak pumps that can’t give much head pressure. An example would be the Swiftech MCW 6002.

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Impingement Blocks: these are the cream of the crop, top notch water blocks delivering high performance. However, this obviously comes at a price. These blocks range from mildly restrictive to extremely restrictive. The impingent blocks should only be bought in par with a very powerful pump. The basic concept of this block is to shoot the incoming stream of water into a “pin matrix” design. It is a series of pins that are formed into a grid that creates a larger surface area from which heat escapes and can be removed. As a rule of thumb, a larger surface area means a potentially more efficient block. The Swiftech Storm comes to mind as a prime example of this type of CPU water block.

2) GPU Water block

Cooling - Tom's WikiProbably the second most used water block in terms of addition to a water cooling loop, this type of water block is also the most evolved of any of the water block types. As competition amongst the graphics card makers rages on, so have their designs. As of late, Invidia has attempted to keep a particular design structure with their 6800, 7800 and 7900 GPUs and that has made water blocks designed for use in their products easier to keep up with - much more so than ATI. It is possible to use some 6800 water blocks on some 7800 cards and you can use most 7800 water blocks on most 7900 cards but ATI water blocks are more specific. This is, of course, for those water blocks that are “all inclusive” in that they also include video memory cooling incorporated into their design (referred to as "Full body" waterblocks). In addition to cooling the video memory, some of these water blocks also have attachments that will help cool the voltage regulators of the video card.

There are more basic designs which just cool the GPU and you would have to purchase additional “micro heatsinks” to be placed on each memory location to effectively cool the video ram.

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Some water blocks of a more specialized nature include bridges that also cool the voltage regulators on a video card – these components can get very hot.

Companies suck as DangerDen, Innovatek and Aqua Computers have developed even more specialized GPU water blocks that cater to the enthusiast market for video card configurations such as Nvidia SLI and the dual pcb (printed circuit board) 7950GX2.

The Word:

3) Northbridge Water block

The Northbridge, typically, controls memory functions like – a memory controller (for Intel Chipsets), a level 2 cache communicator and bridges the gap between the CPU and Ram – it also handles functions between the CPU and the graphics processor on the PCI, AGP and PCIe slots. Since this particular part is always busy it can generate quite a lot of heat. In terms of water cooling, specific blocks were designed (based upon retention type) for these chips. The retention type refers to the method that is subscribed by the motherboard to hold its Northbridge chipset cooling mechanism.

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Most motherboards (and, hence most chipset water blocks) use a “two hole” method for use with spring loaded plugs or screws. Some motherboards, though, use “hooks” that are applied in two and four hook configurations, to loops that are on the Motherboard – disallowing the use of screws or spring plugs.

4) Hard Drive Water block

Is it any wonder that with the increase in relative speeds and sizes of hard drives that the heat they produce is also increased? Anyone who has ever owned a Raptor Series of hard drives can attest to the heat they generate. That heat can lead to added heat to the overall computer temperature as well as endanger the stability of the drive itself in such an enclosed space if the heat is not dealt with sufficiently. The water cooling world has answered this concern with the creation of hard drive water blocks. Some designs involve enclosing the entire hard drive while others are made with a very basic skeletal structure. The basic premise of each, though, is the same – run water against a surface that is in connection with the hard drive. There are two basic designs:

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Side-cooled Blocks – these are water blocks that hold the hard drive along both its sides and run water through these contact points. These offer the smallest of contact areas but are very popular in their design because of the flexibility they offer within a case. The Alphacool SILENT star, Danger Den Aqua Drive and the Innovatek HDM L-Pro are examples of this. Attachment to the drive is done via screws which go into the sides of a hard drive much like a drive bay rail or guide.

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Top/Bottom Blocks – these blocks are mounted on the top or bottom of the hard drive and cover the entire surface area of its contact point. While they are more effective at moving heat away from a hard drive they are also the most cumbersome to use as they often take up access to a surrounding drive bay. Some of this type of bloc, though, allows two hard drives to be attached, one on top and the other on the bottom. Examples of this type of hard drive block are: the Koolance Hydra-Pak, the Alphacool HDD3 and the Asetek Waterchill Hard Drive Cooler.

5) Miscellaneous

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There are more highly specialized water blocks that are available for particular parts of motherboards and graphics cards – you’ll see them referred to as Mosfet Water blocks, Voltage Regulator Water blocks, etc. These type of water blocks are usually associated with a particular brand of computer equipment like the Mosfet Water block for Nvidia 7900 series video cards or the Long Mosfet Water block for the Abit AW8 Fatality series motherboards. Now that you have some understanding of what water blocks do you can surmise that these water blocks are used to remove heat from a potentially hot source but are more specific as to where they will operate. There are also water blocks available for system memory (Koolance Ram-30) and for video memory (Alphacool MCX ram).

Section 3 Pumps

The pump is a very crucial part of the cooling loop and is the heart of your setup.

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Before we begin, though, I wanted to explain some terms that you might encounter quite often. The first of these is “Head”. For purposes of definition, “Head” refers to the height of a vertical column of water. This is the maximum height that a pump can sustain any semblance of flow rate before it loses its capabilities. For purposes of an example we'll use a pump rated at 317gph with an imaginery "head" of 36 inches. At 0 inches of height you will have maximum flow rate and the pressure will be zero. Pressure is a measure of resistance to flow. Thus, at its initial discharge, at 0 height, the pump experiences its least resistance and generates its fullest flow. As the height in the cooling loop increases, the resistance to flow increases and the flow rate decreases. Earlier we said that our pump had a "head" of 36 inches. The closer the pump gets to its "36 inch" height, the less flow is generated.

So, at 0 height we have 0 pressure and 317gph. At 36 inches we have full pressure and no flow.

The second term I wanted to explain is liters and gallons. Some pumps rate their flow at liters per hour (lph) and other at gallons per hour (gph). 1 liter is .264 gallons. 1 gallon is 3.785 liters. So, if a pump has a flow rate of 1400 liters per hour then the equation would look like this: 1400 (liters) * .264 (gallons) = 369.6gph. Likewise, if a pump has a flow rate of 317gph then the equation would look like this: 317 (gallons) * 3.785 (liters) = 1200lph

For purposes of classification, we’ll touch on two different categories which will themselves have to different classifications within them. In terms of power adaptation there are two types of pumps – 12v and AC. The most obvious distinction is that the 12v draws power from a direct connection to your computers PSU via a standard 4-pin molex connector. The AC pump uses a power cord that connects to a wall outlet. Modifications are possible for the AC pump to use an internal relay switch from which a power cord can be utilized but does not have to invade the computers structure. Having a relay switch with an AC pump also serves to turn the pump on when the computer is powered up. Relay switches come in several forms and will typically occupy a standard PCI access slot on the back of your computer. Some, though, might require a little modding work on the case.

Also, within these two types you will find that pumps can be further subdivided into “submersible” and “non-submersible” pumps. Submersible pumps are those that are encased within a reservoir, underwater so to speak. Alphacool’s Laing brands of pumps are submersible.

However, you will most likely deal with non submersible pumps over the course of your water cooling experience. With that in mind let’s distinguish between the AC and DC (12v) pumps. What you will find is that the AC pumps are going to be the most powerful. They are also the largest and most expensive. Bigger does not always mean better in this case. It might be more accurate to say that bigger or more powerful does not always make a pump practical. The relative size and power of larger AC pumps might prove less advantageous due to the sheer space that they occupy. While more flow means a better cooling loop, in the case of some of the larger AC pumps, their size can become an issue. Take the Hydor SELTZ L 45 II – it pumps water at an incredible rate of 950 gph (gallons per hour). That’s a lot of movement. But, the pump itself stands a full 7 ¼ inches tall and is 7 ¼ inches long and has a width of almost 4 ½ inches. There aren’t that many cases that could even begin to think about housing that unit. Of course, such a pump is more normally used to cool more than one computer at the same time but you get the idea. The Eheim 1250 pump is a slightly less powerful when compared to the aforementioned Hydor but as an AC pump it is still quite large. While it pumps water at a high rate of 317gph, it too is very large at just over 7 inches long * 4.7 inches tall * 3.8 inches wide.

DC pumps, though, are considerably smaller and, as a general rule, are less powerful although, some are as powerful as their AC counterparts in certain cases. Drawing their power from your computer’s PSU, they are much more convenient to use and have a much smaller footprint than most AC pumps. One of the most popular pumps on the market is the 12v MCP 655 (Swiftech) which is also the same thing as the DD-D5 or Laing D5 (Danger Den). It is a very powerful pump when you consider its size relative to the flow rate it creates. At 317gph it is as powerful as the Eheim 1250 but it is only about 4 inches long * 3 ½ inches wide * 3 ½ inches tall. This particular pump is also silent running. Basically, the only way to tell that it is running is the turbulence created by its flow rate.

Section 4 Radiators
A radiator is, simply, a heat exchanger. It is designed to remove heat from any liquid moving through it onto a row of “fins” from which the heat “radiates”. There are quite a few notable companies who sell first rate radiators – Danger Den is probably the most well known – then there is Swiftech, Alphacool, Thermaltake, Corsair and Thermochill, to name a few. Radiators come in varied sizes, largely based upon both size and number of fans employed. They can be found in single, dual, triple and larger configurations. Two fan sizes are used in radiator design (generally) – 80mm and 120mm. Furthermore, fan mounting holes are placed on both sides of a radiator to allow for flexibility in mounting, fan placement and whether or not the air is “pushed” or “pulled” through the radiator. Radiators can be mounted internally or externally. As it was earlier mentioned, air can be “pushed” or “pulled” through the radiator fins depending on how the fans are arranged. There is a popular method whereby fans are placed on “both” sides of a radiator. Known as “push-pull”, fans on one side of the radiator are set to “push” air through the fins while another set of fans, attached on the other side of the radiator, are used to aid in “pulling” the air. This method is used to maximize the potential to a greater degree than a single row of fans. Shrouds are also used to further enhance the efficiency of the fans and air movement through the fins of a radiator. A shroud is a “plate” (with fan holes for 120mm or 80mm fans cut through it) that is laid between the fan and the radiator. They seal the area around the fan and radiator so as to allow for a more directed flow of air through the pathway into (and out of) the fins. The benefit here is that there is less air disruption from gaps between the fans and radiator where a complete seal is not otherwise found.

Single-Pass and Dual-Pass Radiators
Think of a row of tubes, being a parallel row of tubes from one side of the radiator to the other. Imagine it as being like a slice of bread, with tubes running from one end to the other. A single-row radiator is like a single slice of bread. A dual-row radiator is like two slices of bread together.

Single Pass

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In a single-pass radiator, the coolant flows from the inlet at one end, straight through all the tubes all at once, to the outlet. Single-pass benefits because it presents all the tubes with the highest possible water temperature at once (whereas a two-pass radiator will only get the highest temperature inlet water on one side, and then cool slightly cooler water up the other side. This doesn't make a huge difference though. Generally it provides a 1-15% performance benefit from this effect alone).

Where single pass falls down, though, is the tubing velocity. Because the water is presented to all the tubes at once, the water velocity through the tubes is half of what it is through a dual-pass radiator. As the flow rate (and hence water velocity in the tubes) goes down, the radiator performance starts to fall away. With a single-pass you've gone and halved the water velocity in one hit. This is offset somewhat by the temperature delta benefit of single-pass, but it is by no means a sure thing that single pass will be better.

Dual Pass

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In a dual-pass radiator the water flows down one half-side, U-turns, and back up the other half-side. For multiple row cores, dual-pass is always better and flow restriction doesn't really come into it. The vast bulk of the flow restriction in these types of cores all comes from the fittings. The pressure drop difference is insignificant when water blocks are involved, so long as the radiators have correctly designed end-tanks. Higher CFM fans are more suited for this type of radiator.


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Reservoirs are receptacles for holding a volume of water that is cycled through the cooling loop and for trapping air that is existent in the water flow. This is an extremely populated category of water cooling component as there are so many different types of reservoirs available. For purposes of giving you a basic understanding, this guide will discuss the most commonly designed models.

The most basic design of a reservoir is a container with two screw holes and a cap. The screw holes will have some form of thread size to which various fittings will mount. These threads allow a person to adjust the ID size (to a point) based on the ID theme of the cooling loop. The cap is where you pour your coolant to fill the tank. Since there are so many different types of reservoirs, you won’t be lacking for a design to choose from as they come in such shapes as (but, are not limited to) cylindrical, rectangular and circular.

There are a varied number of ways that reservoirs can be mounted – in the drive bay, suspended by specific clamps, mounted in fan blow holes, etc. I think you get the picture – there are a number of options available to any person as far as reservoir design and method of placement. Some reservoirs are more highly specialized in that they have multiple thread holes for enthusiasts who may have need for more than a single cooling loop in their system. This type of reservoir allows for a convergence of the loops into one source of coolant. Reservoirs, while chiefly made of acrylic, can also be found to be made of many other materials (i.e. aluminum, delrin, etc.).

It should be noted that some enthusiasts forgo the use of reservoirs in favor of “T” fill lines or “Fill and Bleed” kits but for purposes of this guide, they aren’t going to be discussed.


Tubing, basically, is the medium that is used in the transportation of liquid coolant from one point of a cooling loop to another. The size variations include (but are not limited to) ¼ ID, 3/8 ID, ½ ID, 5/8 ID and 7/16 ID. Also, tubing wall thickness can be varied amongst the same ID size – this influences both bend radius and ant kinking properties as well as flex fatigue. Flex fatigue is the ability of the tubing to maintain its bend radius without collapsing over time or usage. Tubing’s importance is often overlooked – much in the same vein as the way power supplies are chosen when constructing a computer. However, it is to an enthusiast’s folly that they do not take the significance of this component more seriously. The importance of tubing cannot be overstated by any means as there are so many factors that both influence tubing integrity and are influenced by the tubing’s quality.

There are so many different types of tubing in the market that it gives an enthusiast a number of options with which to base their choice. Factors such as chemical resistance, kinking, price, memory, bend radius, permeability, flex fatigue and discoloration are but a few of the characteristics to consider when deciding upon tubing.

Of the many varied tubing products available to an enthusiast, tygon, Clearflex60 and Primoflex are of the most abundant. Of the three, tygon is considered as being the premium product. It is also the most expensive (in some cases, twice the cost of Clearflex). Primoflex is the cheapest alternative of the three.

In almost all phases of tubing characteristics, Clearflex60 is a viable alternative to the more expensive tygon – kinking, bend radius and flex fatigue. But, where tygon gains its advantage is in permeability, chemical resistance, wall strength and memory. Clearlfex60 uses a standard 1/8 wall size compared to 1/16 of the tygon tubing on comparative products. Of course, there are also specialized wall thickness sizes for each product like ¾ OD, 11/16 OD and so on. tygon tubing was designed to be a premium lab grade product and, thus, specializes in chemical resistance and permeability. The best example of this when compared to Clearflex60 is discoloration over time. When you are funneling coolant through a water cooling loop, tubing will generally begin to discolor over a prolonged period of time. This will be evident in the degrading effect that is witnessed in the tubing’s opacity. What happens is that as the coolant travels throughout the loop, the tubing’s permeability has the effect of “collecting” a buildup of the coolant along its walls and that is evident by the “cloudiness” that most water cooling loops experience. tygon tubing is much more resistant to this effect than any other tubing product and maintains its clear visibility much longer.

Primoflex is unique in that, besides being an even cheaper alternative to Clearflex60 and tygon, it also comes in UV reactive wall designs – red, blue and green. Primoflex is adequate with respect to the other characteristics of tubing and measured along side Clearflex60 and tygon but, falls short when measured up against them. Also, Primoflex will not work with compression fittings.

So, the most abundant tubing offered to potential water cooling enthusiasts is standard Clear PVC, Primoflex, Clearflex60 and tygon. However, there are a myriad of other products – each offering their own testimonies - such as Thermaltake iTube, Mazzer, Masterkleer, Silicone, Polyurethane and Aqua Computer’s Plug & Cool to name a few. You will not be lacking for options when choosing tubing for your water loop(s). The choice of product will be based on your budget and/or desire for level of quality and characteristics.


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Fittings, in short, are the connectors through which tubing is attached to a component in a water cooling loop. This component can be anything from a water block, reservoir or another piece of tubing. They can come in all the various standard sizes (1/4 ID, 3/8 ID, ½ ID, etc) and perform various functions based on their design.

For water blocks you’ll have fittings with a specific screw thread that will offer various sizes. For example, A Danger Den Koolsah GPU water block uses G1/4 screw threads for its connectors. Based upon the ID theme of your cooling loop, to use this water block you would have to get a ¼ ID, 3/8 ID or ½ ID connector with a G1/4 screw thread on it.

The same thing can be said for virtually any type of water block as well. They all have specific screw thread sizes (some of the more common ones are 9/16 straight, G1/4, G1/8, 3/8 BPP, etc.). Connectors with specific thread sizes and tubing sizes are also found on reservoirs and radiators. It is important to pay attention to, not only what component you are purchasing but also the thread and connector size available for that part, not all connectors are offered in all sizes and the same can be said for the threads as well – not all thread sizes offer tubing connectors for all inner diameter sizes. A common thread size for ¼ ID and 3/8 ID tubing is G1/8, Because of the rather small channel of the G1/8, it is not offered in anything larger than 3/8 ID because it would be flow restrictive beyond that.

The fittings with screw threads can be found in many variations such as the 90 degree elbow for right angle bends out of a component like a reservoir.

Also, there are many different types of threaded fittings – compression, barbed, quick connect, high flow, plug-n-cool, etc. The most common fitting that you will deal with is going to be barbed or high flow – from which the tubing is slipped over and held in place by a clamp.

There are fittings without threads that are used to direct water in a certain way. They can come on many variations like “Y” splitters and “T” lines. There are also fittings that will allow you to reduce tubing sizes mid-loop (one end of the fitting might be for ½ ID and the other end would be 3/8 ID). You can, typically, find a fitting for whatever function you are looking for.


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Coolant is the medium in a water cooling loop through which heat from a source is transported. There are a considerable number of products available within this category of component that offers a wide variety of advantages and purposes. Coolants will, typically, come in two forms, premixed and additive. In a premixed form, the coolant has already been combined with deionized water in a balanced mixture. PrimoChill ICE and FluidXP are two examples of this. Premixed solutions come with galvanic inhibitors, biological retardants and lubricants in their mixture. In the additive form, a small bottle of coolant is often provided but must be mixed with a proportionate amount of water. Note: Since most water blocks are copper and most radiators have aluminum cores, this creates a battery-like reactive situation as those two metals don’t work well together and promotes a breakdown of their integrity (over time). Coolants have properties that retard this type of reaction. Water does not - which is why you should always used water cooling specific liquids in any cooling loop. Never use regular tap water as there are a number of additives and impurities that would decrease or affect the cooling potential of the water loop. It is recommended that you use bottled water for this. Corsair COOL, Hydrix, Zalman G100 are examples of additives.

Furthermore, there are specialized additives that are designed for specific effects like UV Dyes, which can be added to water loops to give the flowing liquid an ultraviolet light reactive appearance.

There are also specialized coolants that are “non-conductive”. Coming in premixed forms, non-conductive coolants are what they state – non-conductive. The obvious benefit of this type of coolant is that if there are leaks and/or spills in the computer, the escaping liquid will not short out any computer components through conductivity. These premixed coolants are considerably more expensive than the additives. Where an average bottle of additive might cost approximately $4.00 to affect 32 ounces of water, a 32 ounce bottle of non-conductive premixed solution might cost anywhere from $20 - $35.

Galvanic Reaction and Biological Contaminants

Galvanic degradation is a condition that exists when dissimilar metals come into contact and are joined by some kind of electrolyte.

Amongst the materials that water cooling components are made of, aluminum and copper are of the greatest abundance. Radiators are, typically, made of aluminum and the majority of water blocks are composed of copper. When a medium such as water is run through a cooling loop, it picks up particles of everything it comes into contact with and carries them into contact with any surface it interacts. Because these two metals do not react well with each other, it becomes necessary for there to be some kind of inhibitor that will compensate for such a possible reaction. Most coolants have some form of corrosive inhibitor and it is so very important that this is taken seriously. This is one reason why you simply cannot run pure water as a coolant. Not using a proper coolant could result in the shortening of the total life of radiators, fittings and water blocks.

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Most coolants also have some form of algaecide that reduces the possibility of any biological presence from appearing. Besides its unsightly appearance in any place of the cooling loop, algae can clog water block or radiator channels thereby increasing the flow rate resistance and decreasing the components effectiveness.

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In order for a radiator to fully utilize its potential in removing heat, fans must be attached to it to blow air through the fins. This air movement carries the heat away and assists the radiator in sending cooler liquid back into the cooling loop. Chiefly, there are two sizes of fans that you will encounter for rads – 80mm and 120mm. You won’t find 80mm rads or fans in use in a cooling loop as frequently as you will find 120mm though. Typically, a fan is attached to a radiator by way of screws. The direction of the fan can be either pushing or pulling air through the radiator grill. As for which is a more effective method – MaximumPC recently did a study on this very question and the end result was that there is actually very little difference either way.

It is highly recommended that you use Shrouds with the fan/radiator setup. A shroud is a piece of equipment that is placed between the fan and the radiator and is used to seal off that area. Its benefit is that it focuses the air direction straight into the radiator grill, void of any turbulence created by gaps, which will definitely aid in its efficiency. These shrouds are placed wherever fans are attached – on either side of the radiator.

There is a method of fan placement that generates a greater volume of air movement through the grills called “push-pull”. Since radiators have the ability to house fans on either side of its grill, some enthusiasts have used this as a means to force a greater volume of air to be circulated through the fins. In a standard radiator, one fan is attached (with shroud) on one side, directing air through (“pushing”). On the opposite side, a fan is placed (with shroud) pulling air through, thus aiding the air movement. The advantage of this technique is, of course, greater air movement through the radiators fins and thus, better cooling efficiency. However, having additional fans may prove problematic if placing the rad within a case. Externally, the issue lies with power connections as they will prove challenging to find if you are using a dual 120mm radiator (or triple). That is up to 6 fans – all of which need to find a power source somewhere.


Besides the main components of a cooling solution that have been previously discussed thus far in the guide, there are a number of smaller parts that are still of relatively extreme importance in completing a loop. There are also a number of components that, while not absolutely necessary, do offer advantages in maintaining cooling loops integrity.

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Cooling - Tom's WikiTo keep attached tubing from leaking and to help maintain its hold on a fitting, it will be necessary to apply clamps of some form over the tubing/fitting interface. Clamps come in two types, metallic and plastic. The plastic clamps are equipped with alligator teeth that, when squeezed together, for a strict bond that won’t slip. They will maintain their hold on the tubing until they are removed. Breeze miniature hose clamps are metallic clamps that are adjusted by using a screwdriver. They offer certain advantages over the plastic clamps. They offer higher sealing pressure with minimal torque requirements. They are constructed of marine grade stainless steel and are extremely corrosion resistant.

Sometimes, it becomes necessary, when forming cooling loops, to have tight bends when connecting one water block or component to another. The problem with this is that, under certain conditions, tubing can collapse or kink due to pressure or age, To help guard against this, a person can use “coolsleeves” to strengthen the tubing’s walls. coolsleeves are a length of coiled plastic that is wrapped around tubing where tight bends are expected. It forces the walls into equalizing the pressure as much as possible at various points. This will allow for the use of tighter than normal bends.

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radbox Assemblies are used with external radiators. Their function is to act as a standoff between the computer case and the radiator/fans. Typically attached to a 120mm blow hole either in the rear or the top, a radbox assembly will create a gap of approximately two inches between the case and the rad. This greatly aids in air movement around the rad.

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*I would like to acknowledge thanks to shawnlizzle for use of his previous “Water cooling 101” guide and from various sites through which much data was gathered.

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