30 year old boat with fiberglass tanks holding 350 gallons. We don't have a watermaker, instead, we fill up as needed about once a month, or/and,, we catch rainwater. Use the entire boat waiting until after a few minutes of rain washes the deck. We filter the drinking water through a .2 micron (same as Seagull) filter which cleans it up very nicely.

Never been sick and never had bad tasting water.

The trick is to use the boat and cycle the water.