[Bones]

One thing you could do is to install a in-line water filter to help catch what's in the water you use.
Filtering it will help reduce the amount of trace elements that could cause scale and mineral deposits to build up. I've been thinking about doing that with my stuff lately and just may set it up soon. Since we're talking about corrosion and the like, there are chemicals you could use to help too. Also the materials your system is comprised of is important, such as avoiding a Galvanic reaction, not to mention electrolisys (Hope I spelled that right). I've seen pumps literally eaten away internally by that even if the water was treated chemically. Replaced one last year at work that had simply quit moving water because the impeller wasn't there anymore due to electrolisys. It was an old pump but this effect can still be a problem sometimes. I've never heard of a PC WC'ing system with problems from that before but it could happen.

BTW, that's why you hear sometimes of a "Sacrificial Anode" being in a pump system. It gets eaten away by the electrolisys instead of the hardware itself. It in effect sacrifices itself to save the rest of the system.