Soft Water vs. Hard Water
Soft water is a funny thing, because it is really water in its purest form. All of the mineral (namely calcium and magnesium) ions are missing, making the water as close to two H's and an O as possible. But we as humans are not accustomed to it, and it makes us realize the primary beneficial aspect the minerals give to the water - they reduce water's natural corrosiveness. Without those minerals, soft water will corrode the metal parts associated with the plumbing of a pool, jacuzzi hot tub or kitchen or bathroom faucet much more rapidly, making the problems associated with hard water seem benign by comparison.
Who would have thought that water, the element responsible for life on Earth, was such a dangerous thing when not properly tempered by the earth element?! Most people don't have to worry about soft water, since balanced and hard water are much more common, in nature as well as in urban and suburban reservoirs and facilities, but there are those places that have either naturally occurring soft water or where the water has been softened to a certain extent by people.
In swimming pools, hot tubs spas, or when taking showers in soft water you may feel like the sterilizer, soap or shampoo you are using is especially slimy or filmy, and it will lather up much more than usual. A normal portion of such a product could surprise you with the amount of foam is creates, and the feeling that it doesn't want to wash off. Using less of the cleanser may be a sufficient way to respond to the soft water situation, or perhaps getting a showerhead filter that hardens the water. In the case of swimming pools and hot tubs spas, however, using less chlorine or bromine sanitizer could raise concerns about bacteria growth not being prevented as it should be.
Baking soda can be added to harden the water, which is a fairly common practice with laundry, and you should be aware that some water softening agents are sometimes added to laundry detergents, so if this is the case with your detergent you may want to add the baking soda even if your water is not already soft. A washing machine (or a jacuzzi hot tub) will be the perfect place to discover the presence of soft water, because the presence of a mountain of suds will be unmistakable.
If the water to the house is soft, it could be causing corrosive damage to various parts of the plumbing and it is advisable to invest in a water hardening system that can balance the water to the whole house. Of course, hard water is problematic for plumbing as well, and leaves behind the tell tale calcium deposits.
Many aquarium owners are already familiar with the necessity of hardening water for the sake of fine tuning the habitat for certain marine life (namely corals, snails and tube worms), putting specialized commercially available materials like calcium chloride pellets and magnesium sulfate (commonly found in Epsom salt) directly into the tanks. They must be careful to follow the formula carefully to prevent creating a toxic underwater environment.
People are much more resilient, of course, but it is true that hard water can cause skin and eye irritation, and can create a solid soap scum that covers the hair and skin and clogs the pores. Here it becomes evident that one of the best ways to tell if your water is not balanced is to ask yourself whether your skin truly feels clean after washing. If there is a residue, the frothiness of the soap will tell you that the water is soft, and the appearance of stains or scales will signify hard water.