So if you are right Cyclops that the galvanic effect is causing the zinc ions to migrate in, then increasing the voltage should increase the migration. Using the galvanic potential material list I had in my previous thread, Silver would almost double the potential. I looked on the web for silver foil and found
http://www.pinzart.com/catalog/enamel-s11.html
They sell sheets of pure silver that could be wrapped around the copper rod using pressure sensitive adhesive (double sided tape). I am curious to see what effect it may have on the ROP. If it is really the zinc I guess I'll bag the idea of trying an aluminum based ROP. I checked with some engineers here at work and they said that foil would have the same performance as a solid rod. It just would not last as long. But length of service for an ROP versus a corrosion inhibitor on a sea going boat is not comparable. The foil will last just fine for this application and if it were to wear out, a new layer of foil could be added. Also, since the silver foil is key and the base material is not important, one could use a much lighter material like a 1/4" polyethylene tube. This would mean the heavier bar is on the bottom making it easier to stay in position. Further the lighter the whole ROP, the less strain on the latex tubing which loosens over time.