How do we determine 'Mixed metals'?

[Stealth5325]

I'm refreshing my watercooling loop here, and I've got several kinds of metals in it. While I'm well aware that aluminum and copper are considered 'mixed', and will thus cause corrosion when linked with an electrolyte (water), I'm not 100% sure how I can tell if my actual loop contains metals that are sufficiently different to create the same effect. I'm running:
Copper (waterblocks and rad)
Nickel (plating on the inside of my Bitspower compression fittings)
Silver (IandH's killcoil)
Brass (fittings).

Do I need a corrosion inhibitor?

[millertime359]

Nope, those are all fine. :up:

Putting aluminum in that loop is when you have to worry as you thought.

[Sadasius]

Just add some Lithium and you will have a show. :up: You system is fine for metals.

[zanzabar]

u have to make sure that the elecro negativity is within .2 but i would aim for .1

there is a chart on the wiki
http://en.wikipedia.org/wiki/Electro_negativity

[voigts]

Those metals are used in watercooling parts because they play well together without corrosion issues. Thankfully the issue of corrosion with having alu and copper in the same loop has gained enough attention that watercooling parts manufacturers are using aluminum much less than in years past.