Making sure your pool water is always balanced correctly is very important. 

Technical Terms:-

pH

pH scale runs from 0 to 14 and is a measure of the acidity or alkalinity of a solution. This is a very important concept. It will be very difficult to get the best out of a pool unless the pH is correct. It is recommended that the reading be kept between 7 and 8.

Calcium Hardness

Calcium hardness is the amount of dissolved calcium (plus some other minerals like magnesium) in the water. Too much calcium means cloudiness and scaling up, too little could lead to the water satisfying its appetite for calcium by taking it from the grouting.

Chlorine Stabilizer

The chemical name is cyanuric acid. It is also sometimes called conditioner. Low levels of stabilizer are beneficial because they prevent wastage of free chlorine by the UV waves in sunlight, but high levels are a disadvantage because they make it take longer for the chlorine to kill micro-organisms.

Algae

Algae are microscopic plants which can literally transform the pool water from clear blue to the appearance of a stagnant pond in 24 hours. They are introduced into the pool by airborne spores, from make-up water, from covers which have been dragged over grass and moss and from vegetable matter. Onset is quite common after thunder storms, especially if the water temperature is high. Algae take up dissolved carbon dioxide and therefore cause the pH to rise rapidly. There are hundreds of different species of algae – some green, some yellow (“mustard algae”), other black or even pink. They can be the clinging type and colonize the pool surfaces, or float suspended in the water. Normally not a problem if chlorine levels are maintained.