heheh. Post what rad you have btw.
Non-Conductive is a fancy way of say there is a resistance to electricity. Electricity accels in high electrolyte filled water or anything else that helps act as a conduit. Hence why salt water has a very high resistance to electricity because there is so much salt and other minerals that resist it's flow. (I'm not saying use salt water either. hahaha) Also true non-conductive would be deionized water.
Anyways distilled water is actually has a low conductivity as well. This is why you will see it mentioned around the forums very often. In regards to the post Mega Man posted, Martin is a very famous water cooling enthusiast around the interwebs. Water cooling is a small community in the grand scheme of things so when someone steps up and makes a break-through, people tend to notice. As Martin said distilled water is the cheapest and best solution considering almost anyone can get there hands on distilled water.
In regards to Mayhem (Mick). I've asked him about his H20 before and it mostly pertains to people in Europe where the water quality may not be as high as it is here in the United States. So Mick had contracted out his own version of distilled water which is as good as it is here in the states. Now if anyone reading this is in EU, then by all means perhaps buy Mayhem's H20 for PCs. Moving on!
The Galvanic Scale or Galvanic Corrosion Scale is most commonly used in plumbing and roofing. This stems from the notion that contracts who deal with residential, commercial, and industrial sites must know how to use there materials properly or corrosion will ensue. Regarding the galvanic scale in your case has to do with the use of aluminum and copper in your loop. Here is the reason on a very basic scale.Galvanic Scale (Click to show)
As you can see aluminum has a 2 and copper a 10. polar opposites of each other if we will. This tells us that there is a very high chance the two materials will cause the other to corrode. In this case sense copper is higher on the scale and thus less protective, the aluminum will cause the copper to corrode. This is why the Statue of Liberty looks green.Statue of Liberty 1886 (Click to show)
Now let's head back to deionized water. Deionized water is where water literally had the ions taken out of it. This is harmful to copper in the sense it can pit the copper and damage it. This is why no one used deionized water either.
Onto your loop. You said you had aluminum, then copper/brass plating and probably some traces nickel depending on the type of fitting you may have. Another reason is get rid of the aluminum is that brass is susceptible to corrosion too. Though the problem is we can't use Brasso on our loops to make it better. haha The best bet for you to do it to take normal distilled water from the grocery store and use it. Before that I'd flush your loop with warm tap water and see if any gunk comes out. Then if you are daring take apart your blocks to check the channels for any corrosion or crap build up. Then flush the loop with distilled water to remove trace elements of minerals from the tap water, chlorine, zinc, etc. Then run 100% pure distilled and call it a day. Some PT Nuke could work or a silver coil if you don't have any nickel. If you want dye make sure you use only a little and find a dye that has a huge concentration from a small drop.
I.E. 1 drop will completely color 1 LTR of water. The reason there is that dye come from a solid first then then is transformed in a liquid using centrifuge and other such methods. But all dye is either a powder or more likely a block of coloring first. If you have any other questions then feel free to post them.