It only makes sense to talk about pumps after reservoirs, because as you know, the pump always comes after the res! Water cooling pumps come in many many sizes and flavors with the most popular being the Laing D5. This pump is a slightly larger cylindrical design that is known to be extremely long lasting and very powerful. You can find it manufactured by many companies and called either a D5 or MCP655. There are a couple of variations, one is just the straight 12v pump the other is the variable speed version. There is also a version known as the D5 Strong which follows the name and is a higher flow version of the same pump. The standard D5 comes with the motor mounted in a plastic chassis and has two barb type connections for inlet and outlet. There are aftermarket kits to mount the motor in an aluminum housing with multiple inlet and outlet flow paths cut into the aftermarket top. Additionally you can find both bay and tube type reservoirs that incorporate the pump directly into the res. If you like the look this can save you some time and hassle getting the pump connected correctly.
After the D5 the next most popular option would be one of the DDC variants. These pumps are much smaller and more square in shape. Essentially think square hockey puck. There are versions for whatever scenario you can imagine and are popular in small form factor builds due to their size. In general they tend to have a higher pitch whine than the D5 and are not known to be as reliable. For these reasons they are less popular but are still an excellent option.
There are of course of ton of other pumps available for water cooling. Some are even cross overs from aquarium pumps. For whatever reason, price, size, reputation of reliability, the D5 and DDC types easily hold the largest segment of the market. If you choose there are still great pumps aside from these two, I would only suggest to do your research before buying. Reliability and flow are key when it comes to water pumps. Without a strong flow the loop will build up heat around the components we are trying to cool and can adversely affect your PC’s performance and longevity. And the last thing you want is pump failure on a highly overclocked PC that is running without you around. While it will not overheat immediately it will slowly build heat until the water in the loop is saturated and then start to hurt your system and can lead to part failure. Buying a quality pump is very important.
Let’s talk tubing! Again so many options available where do you start? Simple, start by choosing what size tubing you are going to use. Bigger tubing = less restriction = more flow. And we know good flow is key to proper cooling. Tubing is described using two measurements. ID: Inner Diameter which is the size of the passageway which the water flows through. OD: Outer Diameter the size of the tubing on the outside. The larger the variance between these two numbers the thicker the tubing will be. This will be important to you when you are building the loop. Thicker tubing is less flexible and harder to work with while tubing that is too thin will collapse and kink when you try to make it bend too sharply. You can avoid most of these problems with a properly laid out loop. Unfortunately as the loop becomes more complex some things become unavoidable. So what tubing do you actually want? The most popular size is ½” ID x ¾” OD. This size is not so thick that it can’t be worked with but is thick enough that unless you are making some extreme bends it will not kink. The ½” ID is also large enough that it will flow extremely well. The downside is that it is somewhat bulky and might not be the look you are going for. For a first time builder this is still always the size that I recommend.
Now that you know about size you simply need to select brand and color. Color is almost entirely up to personal preference. Going with colored tubing ensures a consistent color for as long as you use that tubing. One thing to keep in mind is that sometimes the color you order doesn’t quite look the way it does in the photo i.e. blues can be more purple, etc. The other option is clear. Clear is awesome if you are looking to add some dye and/or just like the see through look. The downside is that clear becomes more opaque over time and can be stained with the dye you use. The opaqueness is due to a chemical called plasticiser (it makes the tubing flexible without cracking) breaking down in the tubing and floating around the loop. This chemical makes it important to choose the manufacturer of your tubing carefully. I can make recommendations, but it is really best to search around the internet right before making your purchase to find out who is making good tubing at that time. In the past this has change from month to month. Big names to look at for good tubing are PrimoChill, Masterkleer, and Tygon. Tubing can usually be order by the foot or in precut lengths. Guestimate how much you think you will need and always order several feet extra. You do not want to be short on tubing when you are finishing your loop.
In order to connect your tubing to your components you will need some fittings. If you’ve already read my intro to Water Cooling 101 you will know that there are two types of fittings, barbs and compression. Barbs are simply metal tubes with ridges towards the tips that press against the inside of the tubing. They are secured with clamps on the outside. Compression fittings on the other hand have a barb type fitting on the inside and a metal ring that tightens over the outside of the tubing via a screw mechanism until the tubing is secured.
Compression fittings when tightened correctly form a stronger seal than standard barbs but are more complex thus they cost more money. If you can afford them compression fittings are the much better choice. The price difference however is quite large, think 2.5 times more expensive for the same part. Recommending fittings is actually sort of difficult. The reason being every case and set up is different. For sure you will need at least one regular barb or compression fitting per connection. In the standard loop we’ve designed you will need 8. If you want to add a drain line to your loop it will require three more plus a three way splitter and a stopper for the end.
If you have some hard angles you might choose to add some 90° fittings or maybe some 45° fittings. These fittings come as standard adapters, rotary adapters(part of the fitting is able to rotate 360°), or combo adapter/barb or compression fitting.
You might also find that you need to get a fitting away from the part it is connected too. In this case you can use an extension fitting.
For the simple loop we are building I would suggest the eight fittings (compression or barb) and maybe a 90° adapter or two if you think you might use it.
Fittings are designed to be used with a specific size of tubing. The ID of the tubing will tell you the size of fitting you need for that tubing. With compression fittings the OD of the tubing will match the size of the compression ring. So a standard barb will be purchased as a ½” barb, while a compression fitting would be a ½” x ¾” compression fitting for the same size tubing. While there are a couple of size holes that parts are made with the standard tap size is G1/4. This size will provide all the flow you need and most parts are made with this spec and using it will make finding components that match much easier.