Danger Den MCT-5 and MCT-40 Liquid Review

Cooling/Water Cooling by KeithSuppe @ 2005-01-29

Danger Den has partnered with Midwest Cooling Technologies to bring two non-conductive cooling liquids for the H20 Enthusiast: MCT-5 and MCT-40 are premixed, non-conductive, and with significantly lower freeze points then water. They even fluoresce under black light.

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Danger Den MCT-5 / MCT-40 cooling solutions

Danger Den has contributed a great deal to the water cooling industry especially for USA enthusiasts who have somewhat limited choices compared to our Euro neighbors across the pond. Anyone familiar with water cooling has heard of Danger Den's performance oriented copper block's, but the Oregon company offers much more in the way of water cooling systems as an alternative for today’s PC's. It's this thinking which led the company to partner with Midwest Cooling Technologies to offer an all in one cooling solution for water cooling systems.

Madshrimps (c)

Each solution offers basic ingredients with properties essential to a water cooled system, and its ancillary hardware. To simplify, they cool, eliminate algae growth, and if they ever should leak, are non-conductive. This latter property is perhaps most important. From personal experience I've twice had water slowly leak onto a $700 PCI-E video card, and that same card will be used in the test set-up today (luckily). While distilled water saved my card in the first two circumstances, there's a problem unbeknown to many distilled water users. As temperatures decrease conductivity may potentially increase, and distilled water may not have all potential electrolytes completely removed. The quotes below should clarify the difference between distilled, and de-ionized water.

"Distillation entails converting water from the liquid state to the gaseous state and back to liquid again in an apparatus called a "still," comprising a boiling vessel to vaporize the water and a cooling unit ("condenser") to return the water to the liquid state. Most dissolved solids are left behind in an increasingly concentrated solution, so that the boiling point of the liquid water increases...

Deionization entails removal of electrically charged (ionized) dissolved substances by binding them to positively or negatively charged sites on a resin as the water passes through a column packed with this resin. Because the resin also collects other dissolved substances that can feed bacteria, it is not unusual to find bacterial growth in a deionization column. However, the water that comes out of one of these is usually very low in conductivity — the solutes that enable electricity to pass have been removed"

Source: http://www.madsci.org/

From these quotes we see there's a marked difference between distilled vs de-ionized water. I mention this because of the obvious cost differences between distilled water, and Danger Den solutions. Providing we’re seeking the same basic properties in our coolant: non-conductivity, anti-algae, and anti-corrosion, a gallon of distilled water will cost approximately $1 USA, a 120ml bottle of Algae Destroyer costs about $4.95, and a 355ml bottle of Red Line Water Wetter another $5.00 USA. A 32-oz bottle of MCT-40 costs $21.99 at the Danger Den store. The distilled water, anti-algae, Water Wetter combo will give many applications, while MCT-40 or MCT-5 will give just one or two depending on reservoir size and tubing diameter. So what are some benefits MCT-40 and MCT-5 offer distilled water cannot? Let's take look at specifications as printed in Midwest Cooling technologies product pamphlet.

Danger Den MCT-40 / MCT-5 Specs
MCT-5 / MCT-40 Non-conductive
MCT-5 / MCT-40 Anti-algae
MCT-5 / MCT-40 Lubricating Properties
MCT-5 / MCT-40 Anti-corrsion Inhibitors
MCT-5 / MCT-40 Fluoresce under black light
MCT-5 Freeze Point -5F / -20C
MCT-40 Freeze Point -40F / -40C

The pamphlet also states; "...the anti-foaming coolant...lowers the water temperature..." While a reviewer shouldn't be biased I must confess I respect above all, honesty in advertising. Danger Den has always (as far as I've known) been honest and their statement to me proves this. They contradicted the water-temp reduction claim made in the pamphlet supplied by Midwest Cooling, stating water-temps may in fact increase (if just slightly) over that of distilled water. As your about to see the test data will support Danger Den's counter-claim. I used Alphacool's Xtreme Pro Set substituting the NexXxos XP for their BOLD water block and measured water temps directly by placing a Cooper Instruments Bi-metal thermometer into the Coolplex reservoir. CPU temps were measured using Abit µGuru software which reads the P4 550's internal thermal diode output, and ambient temps via a thermistor from TTGI's Fan Master.

test System
CPU Intel P4 550 Retail-3.4GHz LGA 775
Mainboard Abit AA8 (BIOS 17) Combo
Memory Corsair 4300C3PRO 1024MB kit
Video ATI Radeon X800 XT PCI-ex
Power Supply OCZ PowerStream 420W
Operating System Windows XP SP2

Madshrimps (c)

The data indicates MCT-40 performs better under extreme temps, while MCT-5 performs ideally under normal conditions. This seems to validate manufacturer design claims by virtue of the freezing points, MCT-40 being an extreme cooling fluid perhaps for those whom apply active cooling (Peltiers) in their H20 systems.

Finally for the most important test, I utilized a Fluke 179 digital multimeter resistance value which indicated both fluids were non-conductive. I also placed a small cup of both liquids in a -17°C/0F freezer approaching a week now without either liquid freezing.


Danger Den continues to offer all encompassing products which assist H20 users in making water cooling uncomplicated. In this case this hasn't distracted Danger Den from what they do best (in my opinion) design and build high-performance copper coolers. While it's true MCT-5 and MCT-40 are much more costly then distilled water alone, one must remember the additional cost of anti-algae, and Water Wetter which then raises the cost significantly. To be honest I'd rather have the pre-mix done by the professionals and not have to worry. I employ some extreme cooling from time to time and recently found water had actually froze in my line, and in the pump. While this is obviously a rare occurrence it was none-the-less scary to hear my pump spinning wildly as I didn't even notice ice had formed. However the bottom line here is this, do I think this product is worth its $22 price tag? There's nothing worse then the knowledge you've had a slow leak and you've potentially destroyed a $700 video card, and $170 motherboard as leaks occurring at the water block will inevitably pool on top of the graphic's slot (or slots with SLI). If you want to see a close-up when I discovered water droplets in my Abit AA8 PCI-ex slot after removing the card having no idea I had a slow leak for at least a week, take a look here. So do I think it's worth it for such security? YES, $22 to save thousands (if everything fries) is a small insurance fee. I'd like to thank Danger Den for the evaluation samples.

Questions/Comments: forum thread
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