Water… Can’t live without it.
Water is usually softened by exchanging the calcium ions for sodium ions. Some magnesium and even less of other metals are also exchanged. We like this because calcium in the water forms calcium carbonate (lime). This clogs plumbing fixtures and leaves water spots. Other stuff in the water will remain when the water evaporates, so soft water can leave spots, too. Calcium also interferes with soap, so calcium free water lets soap do its job better. Sodium has a distinct taste which some people do not like. If you are on a reduced sodium diet, you should discuss drinking soft water with your doctor. Calgon or Borax can also sequester metal ions, but everything remains in the water, it simply removes the metal ions from playing with the soap. This works well when washing with hard water, but I would not care to drink this soup routinely. Borax also has marvelous uses in swimming pools, but that is a long story. Soft water will not cure a bad level sensor, but it may prevent it from going bad. Boaters often add vinegar (acetic acid) to their holding tanks to dissolve the calcium that when added to urine makes a really hard substance that coats everything. If your fresh water tank gauge is not working, you can try vinegar or a phosphoric acid cleaner. Circulate the solution through the system to clear faucets and pipes and let it sit in the tanks for as long as you can. You would need to fill and flush the system several times to get the acid out. If you see a scale on your holding tank pipes, dump a gallon of vinegar into the tank. Let it sit for as long as you can before dumping.
Chlorine is an excellent disinfectant. If there is any free chlorine in the water, it is disinfected. I would never bring water up to 1% chlorine. That may be poisonous; it certainly would very bleachy as bleach is generally between 5.24% and 6% chlorine. In fact, most municipalities are limited to 10PPM chlorine in the drinking water. One teaspoon of bleach in 100 gallons should result in about 1PPM chlorine. Well water routinely has some sulfur in it. There are pretty common bacteria that convert this free sulfur to Hydrogen Sulfide. This is the compound that makes rotten eggs stink. So if your water stinks it is most likely caused by these bacteria. A few teaspoons of bleach in the water tank will kill the bacteria causing the odor. Circulate this water throughout the system also as the bacteria can hide anywhere. Then a teaspoon or two every other thankful should control any stinky water problems.