this information came with the system also, and i thought i followed it to the tee... i guess this is why i'm interested in finding out exactly what the 'norm' is for the life of a silver rod... this system is excellent, and i would certainly recommed it to you, as i think the question for me is with the rod lifespan... with the smaller system (cs300) different manufacturer, i was getting one gallon per set of silver rods, although i was doing 8 oz. at a time (their advertising indicates 5-10 gal. per set)... perhaps i'm using too much silver off the rods too quickly in the beginning when they are new and full of silver... i so appreciate your helpfulness in this matter...