ok i have saved alot of piping over the years of tank moves, and i have noticed alot of tube worm colonies building up in the piping. usually at the the couplings where they can get a good footing.
if you notice you have to turn your pumps back over the years because your drains cannot handle it anymore, you may have a colony build up. one suggestion i have is try to make your plumbing easy to get to and use true unions to easily remove for clean out.
just and idea i was thinking about, thought i'd share.