It's designed to make it less able to support metal ions in solution
If the alcohols were there as a major proportion of the mixture, that effect might start to become significant. However, if metal salts are less soluble in the solution than in water, that just means the corrosion products will end up as solid rather than in solution sooner... except that the xanthan gum stabilises colloidal suspensions. I don't see it having a big effect one way or the other, but I'm not sure what they were thinking.
The question of whether the corrosion is accelerated by mixed-metal "galvanic" effects is irrelevant here. ("Galvanic" not "Galvionic".)
C'mon, a site that lists water as dihydrogen oxide is gotta be a n00b fisher.
As I read it, the manufacturers used that term in the data sheet they supplied to the people running the overclockers.com site. Presumably they were hoping to impress someone: we agree there.
The alcohol (layryl means it is clear) and glycol is antifreeze
First, the word. The etymology of "lauryl" (not "layryl") is from laurel; my guess is that lauryl alcohol or lauric acid was originally extracted from that plant. Why do you say it means it's clear? Anyway, nowadays "lauryl" just refers to a chain of twelve carbon atoms.
1-Dodecanol is an oily liquid, with a melting point of 24-27C, and it's insoluble in (immiscible with) with water. (Presumably the gum and/or glycerin helps to stop it from separating out and floating to the top.) Being insoluble, it won't affect the melting/freezing point.
The propylene glycol will lower the freezing point: its own melting point is -59C and it is miscible with water.
The lowering of the freezing point will be small given the small concentration of additives. Anyway, does it matter at all? How many people want to chill their water below its normal freezing point?
and the glycerin lubricates the pump (not sure how good that is in the long run).
The mixture might be a little more effective as a lubricant than plain water (but remember that increased viscosity does not mean a better lubricant). I'd imagine that if there were any benefit the makers would be shouting about it though.
Oh, and (I'd have to check but) I'd expect it to lower the freezing point unless there's an awful lot of it: it's miscible with water and its melting point is 17.8C. Also it helps to stop the 1-dodecanol from separating out.
Xantham gum is a stabiliser for the rest of the ingredients. It basically stops them separating out onto your pipes, blocks and pump when the system is powered down.
That's only needed for the lauryl alcohol. It also increases the viscosity, has some lubricating ability and stabilises suspensions.
What you'll find is that after a month or two it will have to be changed as it breaks down
It wouldn't surprise me, but what makes you think it does? (The makers quote a shelf life of five years but say nothing about life in use.)
(common prob with antifreeze).
Really? It lasts for years in cars. What makes you think so?
Waterwetter or equivalent + distilled water is still by far the best method.
I'm not sure that water wetter helps. Certainly some kinds are reported as causing problems. I don't think I've seen any tests showing improved performance.
For inhibiting corrosion, I would recommend "life extender" additives for car engine coolant, or additives intended for domestic central heating systems (the kind with hot water circulating through radiators).
Note that the makers/sellers of this XP stuff say that the liquid itself is not corrosive but they don't say it inhibits or protects against corrosion. Also they don't mention growths of algae, bacteria or fungi, but they do say the additives are all food-grade so presumably living things will do just fine in it. (No, they're not used as preservatives in food.)