### water:

Hard water
* Most hard water contains calcium and magnesium.
* affects pools in several ways.
* better for health because soft water adds more sodium to our diets.
* can also clog plumbing and make water taste bad
  - leave a film on hair, fabrics, and glassware
  - provide significant amounts of calcium
* can cause a build up of scale from mineral deposits
  - off-colors and flavors
  - skin to become dry and irritated and can make hair dry and frizzy
  - white deposits or spots on glassware, dishes and silverware
  - yellowing and rust spots
  - contribute to incompatiblity
  - have high levels of calcium and magnesium
  - leave deposits that weaken or completely cut off the water jets
  - reduce the effectiveness of dairy cleaning chemicals
  - upset zinc levels
* causes films on glass shower doors, walls and bathtubs
  - mineral build-up in dishwashers
  - soap to precipitate, as evidenced by a bathtub ring
  - soaps to curd in the water rather than make a lather
  - toughening of the vegetable skin during blanching and canning
  - unsightly scale build-up on plumbing, and other surfaces
* comes from shallow ground and contains calcium and magnesium.
* contains a great quantity of minerals
  - dissolved calcium and magnesium ions
* contains high concentration of calcium compounds
  - concentrations of calcium ions
* contains large amounts of calcium and magnesium, which reduce the effectiveness of soap
  - minerals which make it alkaline
  - more magnesium than soft water
* contaminated with calcium and magnesium ions enters the exchange column or bed.
* enhances the perception of bitterness.
* gives an alkaline cooking medium which affects color of foods, especially vegetables.
* has a heavy load of dissolved solids
  - relatively high level as compared to soft water which has a low level
* have a tendency to form scale deposits in pipes and heating coils.
* impairs the cleaning strength of detergents.
* increases films and stains from soaps, minerals and other pollutants.
* interferes with laundering, washing dishes, bathing, and personal grooming
  - the action of detergents, and can lead to poor cleaning of equipment
* is also the leading cause of skin problems
  - beneficial to health
* is caused by dissolved calcium and magnesium in the water
  - water passing through rock formations and picking up calcium and magnesium
  - defined by the amount of calcium and magnesium present in the water
  - essentially water containing broken down mineral particles like calcium and magnesium
  - extremely high in alkaline minerals
  - high in calcium and magnesium, while soft water is high in sodium
  - of concern to the homeowner as deposits form on plumbing fixtures and appliances
  - softened by a process called ion exchange
* is water that contains calcium and magnesium salts dissolved in it
  - much dissolved a. Sodium and chloride
  - has positively charged calcium, magnesium and iron ions dissolved in it
* leaves a drying mineral residue on skin
  - ring around the bathtub because of precipitation with soap
* makes washing more difficult by decreasing the amount of lather or suds.
* occurs when large amounts of calcium, magnesium, or iron ions are present.
* prevents iodine sanitizers from working.
* problem that many people face in their home.
* restricts the cleaning function of soap.
* ruins thousands of hot and cold water systems and general household appliances each year.
* seems to be more of an issue with herbicides than with insecticides and fungicides.
* shortens the service life of pipes and chemical equipment.
* tends to leave a calcium build up on the fronds
  - white mineral deposits on the ends of faucets and on shower curtains

Hawaiian water
* are so clear and blue because they lack phytoplankton
  - the favourite breeding grounds for Arctic humpbacks
* have a high percentage of endemic species.