Question for the Experts on mixing these metals in PC water cooling

[SpeedwayNative]

So I am an avid PC water cooling enthusiast and have been running some form of water cooling in my PCs for close to 3 years now. When I initially got into water cooling, I did A LOT of research and "googling" before I ever setup a loop. I decided that I just wanted to use distilled water and either a silver coil or a Copper Sulfate additive to prevent anything biological from growing in the loop. I used the Copper Sulfate additive at first, then switched to a .999% pure silver "kill coil" placed in the reservoir, which I have been using for close to 2 years now. So far, I haven't had any issues with this setup:

Koolance CPU-360 water block - which consists of Copper Cold Plate, Brass Top, N ickel-Plating, Stainless Steel Jet Plate - As far as I know, only the Nickel plating should be in contact with the water in the loop

XSPX RX360 radiator - Copper Tubes and Fins

Various fittings - I am pretty sure that they are all Nickel plated brass

Silver Kill Coil - Antimicrobial .999 Fine Silver Strip

Around June/July EK, a water cooling manufacturer, began getting reports that their Nickel plated Copper blocks were "flaking" or "corroding." They then spent some time blaming this, that, and the other. In the end they issued this statement(below) which blamed the use of distilled water in combination with silver or a Copper Sulfate additive and the Nickel-plated blocks.

http://www.ekwaterblocks.com/index....icleid=83&cntnt01origid=15&cntnt01returnid=17

There have been MANY threads all over the PC community where users are arguing both sides, trying to get to the bottom of the issue. On one fourm they even had a resident expert in the field do some testing on brand new EK blocks to determine what was really going on, the results(below 1) showed that the issue was a Nickel Plating problem, not that silver or Copper Sulfate solutions were to blame. Also,

http://www.sidewindercomputer.com,

a very well respected water cooling distributor went so far as to stop carrying the Nickel-plated EK blocks after they were shown in the testing, linked in this paragraph, to have a questionable plating process and issued this statement(below 2) about this issue.

1:

http://www.realredraider.com/vbulletin/showthread.php?t=47917

2:

http://lib.store.yahoo.net/lib/sidewindercomputers/Corporate06042011.pdf

Now EK is still standing behind their conclusion that the problem is the use of the silver kill coil or a Copper Sulfate additive in distilled water for the flaking/corrosion problems. Well now Koolance (which is what I use) is saying not to use the silver or Copper Sulfate to deter microbials from growing in the loop. Which has lead me to this forum to ask some metal questions for the experts

Here is the chart I am using:

http://www.easternanode.nf.ca/anodic.php

Again, I am no expert in any of this Metallurgy. But from the Anodic Index Chart, in the environment I am using (distilled water, changed no less than 3x per year) I shouldn't have to worry about mixing copper, Nickel-plated copper, Nickel-plated brass, and silver or a Copper Sulfate additive...should I? Note - the silver is not even close to being in direct contact with any of the other metals, as it sits in my Acetal/Acrylic reservoir!

What would the environment I use be considered: harsh, normal, or controlled? - I would think either normal or controlled since it is a closed-loop system.

The 2 metals furthest away from each other in my environment are Silver and Brass, which is a difference of 0.25 V. Isn't this safe from corrosion in a normal environment?

 

[bimr]

It would be considered a controlled environment. You really should have nothing to worry about.

I would put no credence in any of the reports issued by (PC) persons with no background in water treatment. Would you go to a water treatment person and ask for a recommendation on a computer?

In a closed system, water composition remains fairly constant. There is little loss of chemical or water. The most common water treatment chemical that is used in closed systems is molybdate.

http://www.pdhonline.org/courses/m123/m123content.doc

Changing the water is actually making the situation worse. Distilled water when it is first installed will be aggressive (corrosive). After the distilled water has been used, it will lose the aggressive nature as the distilled water leaches metals (corrosion products) over time from the cooling water system.

That is why changing the water 3X per year is probably not a good idea.

Silver is used as a biocide to prevent microbially induced corrosion. Silver should not make the water corrosive.

 

[EdStainless]

The only risk would be changes in conditions (such as pH and oxygen) that might lead to silver in solution then plating out on various parts.
Cu will also work like the silver does, as a biocide.
the targets on x-ray tubes are cooled with water, water that is clean enough to act as an insulator in a 60kV system.
Use good double distilled water,and heat it near boiling before you use it to degas it. vacuum fill the system (removing oxygen and CO2 from the loop). Use your silver wire. Don't change the water.

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