Fresh Water System Cleaning and Maintenance

[kcoffey]

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. And the hot still has an antifreeze smell. 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?

A removal, portable filter is used when filling the tank, and then the filter is drained and dried out for storage until the next time. As it turns out, I probably only use each filter element two or three times before replacing it, just to be sure nothing has a long-term opportunity to grow there. So I doubt that the problem came from the filter.

I really remain puzzled at why the hot water side of the system seems to have retained so much more an antifreeze smell than the cold side. The water heater is pretty small, and was replaced only two years ago. I pumped and drained through both cold and hot outlets in both galley and head before filling the tank, let all of those continue to run through the first part of filling the tank, ran them again extensively after letting the first tank fill slosh around a good bit, and have run the them all lots since. Is there any reason the antifreeze would seem to "accumulate" in the hot water side?

[RichH]

Its the flow dynamics of a cubcial tank.....

The flow characteristics through a cubical tank will leave ''dead zones'' that will take zillions of gallons of flush water to remove/dilute any residual. Most flat bottomed tanks & water heaters will not totally empty when mounted level ... always leaving a little bit of residual no matter how well you think you drain them (only way is to remove & rotate them .... too much problem on a boat).

Do an ''alliquot'' (a mathematical ''trick'' in dilution technique) washing to QUICKLY dilute the residual anti-freeze: fill tank with a few gallons, remove lowest freshwater pipe connection/check-valve and let totally drain (or pump DRY), re-fill with a few gallons into the tank, remove etc.... do several/many times. This will rapidly dilute (mathematically called: exponential decay dilution) the antifreeze that remains.

[JoseASantin]

A carbon filter will remove all the chlorine in the water thus allowing it to go stale quickly. Use a sediment filter to fill the tanks and put an under the sink carbon filter at the output of the fresh water pump for the sink faucets only.