After rinsing the residual antifreeze out of my sailboat fresh water system
extensively, I filled the (~100 gallon stainless) tanks through a simple
carbon filter. Only a few weeks later, the water coming out the galley and
head sinks, cold or hot, has a definite sulfur odor. What are the best
treatments for fresh water system "purification"? Are they all
one-time-through-and rise-out approaches, or are there safe, non-toxic
things that can be left in the water as well?