Retail Box, I am going to order another and send this dead one to Intel.
That was the old way, the Zerex and Hydrx only give a little corrosion protection, thats all they do. The best way to run a loop now (through lots of testing) is with distilled water and biocide (Petra's PT_nuke). Over the last year and a half there has been tons and tons of testing, the stickies in the LC section are horribly out of date.
Galvanic Corrosion happens no matter what when you run mixed metal loops, ie: Aluminium and Copper in a loop. If you run an all copper loop, no problem. It all has to do with the metals in the loop.
No, but you are lengthing the life of your loop by flushing and getting fresh coolant in the loop often. This won't prevent it, but will extend the life of your loop and blocks.
Only the loops with mixed metals (Aluminum in the loop mostly), Copper, brass, nickel and silver can all exist in one loop and be fine. Aluminium is the catalyst (improper word usage I know) to galvanic corrosion.