* The basic parts are water blocks, reservoir, pump, tubing, radiator, and the coolant itself.
* Don’t buy kits.  Just like building your own system, you can get the best equipment if you get the parts individually.  When you buy a kit, the manufacturer invariably must include something they’ve done on the cheap, through materials, manufacturing, or engineering.  Example: the Zalman Reserator 1 (blue) I have is terrific and includes a first class Eheim aquarium pump internally, but the acrylic ‘flow indicator’ that came with it started leaking a few weeks after it was installed.  A second one did exactly the same thing (acrylic is NOT good with glycol).
* Don’t bother with the extra expense of silver over copper, the difference isn’t that much.  Be aware that different metals in your system can have a slow electrochemical effect.  Stick with copper and aluminum.  Don’t use anything acrylic, it will slowly crack during exposure to the glycol.  Polyethylene, polypropylene, and Lucite work great.  The only time I’ve ever had a problem with a leak (*up till now) was due to use of acrylic plastic.
* A high flow rate is not important.  Sure, some flow is necessary, but high pressure pumps will only encourage your system to leak.  You don’t see people putting massively high flow rate antifreeze pumps on their cars because it’s not necessary.  Don’t pay extra for larger jets on the blocks or radiators.  Water cooling is much more efficient than air cooling, no need to waste money on hype.
* Rig your water blocks in parallel, not in series.  This way all the parts get fresh coolant rather than daisy chaining the heat from one component to the next.  This also reduces flow rate, but flow rate is not important!
* Rig the pump to pull coolant from the blocks and push it into the reservoir.  The pressure difference between the coolant and the outside should be a vacuum where it’s most dangerous to leak.  In this way, if there’s a break in the tubing, the pump will pull air into the system at the break rather than spray mildly toxic coolant all over your live hot running computer, carpet, walls, ceiling, face, and pets.
* Use of a rheostat to adjust the fan in front of the radiator will help reduce noise.
* Assemble and test (with water) the whole system before trying to install it.
* Mix:

  • 16 ounces of premium automotive grade ethylene glycol antifreeze

  • 6 ounces of Redline’s “Water Wetter” (half a bottle)

and top off with

  • a gallon of distilled water (about 3 quarts/liters needed)

A plastic windshield washer gallon jug works well.  You will need to replace the coolant every couple of years or you might get algae.  I’m currently using “Zerex”, but if your system is in an area with poor ventilation or in a house with children, you might consider using propylene glycol based “green” (green as in environment, not the color) antifreeze instead, it’s less toxic.

My own system is about 4 1/2 years old now, and has been used on two different motherboards/CPU sets:

  • Zalman Reserator 1 (blue) with integrated Eheim 300 pump, comes with very nice blue silicone tubing, but I didn’t use the Zalman water block
  • 2 Danger Den “Maze 4” copper water blocks with Lucite tops and 3/8″ outlets, custom mounted to two Slot ‘F’ AMD Opterons with strips of brass sheet metal
  • ThermalTake “Aquarius” A1983 VGA water block, nickel plated with 1/4″ side outlets, this is very thin and fits between PCI cards
  • Black Ice Xtreme II radiator with 3/8″ outlets (the Zalman Reserator passive cooling isn’t enough for two CPUs and a GPU)
  • 2 ball-bearing fans for the radiator (120mm), and additional chassis fans for motherboard passive components (definitely needed for a Tyan S2927)
  • A 4-circuit fan speed controller.  This is an unintelligent device, merely a set of 12 volt active transistor rheostats.
  • A “Digital Doc 5” fan speed controller and temperature sensor, this needs no interface to the computer (translation: works with Linux)
  • A few polypropylene T’s and L’s in the tubing.
  • Arctic Silver 5” heat compound

Needless to say, my system is less than easily portable.  I consider this an “anti-theft” feature.

The two separate fan speed controllers require a bit of explanation.  I made a custom cable for the radiator fans, with two separate voltage feeds and diodes to keep the two units from parasitically vampiring power from each other.  The rheostat lets me set a minimum fan speed, which is basically enough to keep the fans running at a minimum of noise.  However the “Digital Doc 5” unit monitors the temperature of various parts of the system, including the double radiator.  If that temperature goes over 96 degrees Fahrenheit, it kicks in it’s voltage, boosting the fan to full speed.  The system runs pretty quietly, but if it gets a little warm, the fans automatically spin up to higher speed.  I run the BOINC application, and so 4 cores of 2 Opteron 2218’s are going 100% all the time, and I’ve never had a *problem.

* News Flash! Problem!

04-JUL-2010 There was an “oh, shoot!” moment when a very small leak suddenly went gusher.  A small but noticeable amount of coolant had leaked from the bottom of the Zalman Reserator, and on investigation, the plastic hose fitting out of the bottom of the aluminum tank body snapped right off.  I believe it was clearly the source of the leak, as the inside of the fracture was stained.  The inlet also showed fracture evidence.  They lasted about 5 years?  Or was it 6?

Anyway… on the 4th of July 2010 (a big patriotic holiday here in the United States of America) and a Sunday, the Loew’s superstore is open and had brass 1/4 ” pipe to 3/8 ” hose barbs.  I discussed a sarcastic tone of sympathy with a gentleman who was helpful in the plumbing aisle, he would have rather been home playing World of Warcraft and appreciated that I needed this plumbing to fix my computer.

The coolant is wiped up, the table is wiped down, the brass fittings went into the tank threads with teflon plumber’s tape, and it’s working fine.  O’Reilly’s automotive store had more Water Wetter.  I’m slightly curious to know if I’ll see any electrochemical weirdness with the brass screwed into aluminium in glycol, but that wouldn’t seem to be as dramatic as a cleanly severed line pouring coolant onto the desk.  As I was actually placing an old cake pan under the tank when trying to figure out the source of the leak, it could have been much, much worse than it was.

I suggest replacing the plastic fittings on the bottom of Zalman Reserator cooling pumps with brass fittings if the unit is used more than a few years.

This leak began without much provocation, the unit hadn’t been moved in months.  The strain on the plastic fittings was never really that much, but it seems apparent that the constant vibration of the pump was enough to cause stress fractures over a long period of time.  I can’t blame Zalman for this, but an upscale model might replace these fittings with something a little stronger.

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