1. Field of the Invention
The present invention concerns a water purification system for a swimming pool, spa or fountain, which is simple to operate, low in maintenance, and highly reliable.
2. Description of the Related Art
In general, the pleasure of owning a swimming pool is tempered by the complexity of maintaining the water quality. Maintaining the water chemistry in a conventional chlorinated pool involves constant monitoring and maintaining the correct pH, free chlorine, available chlorine, etc. This improper balance of water chemistry is most commonly caused by the addition of one or more chemicals to correct one problem, but in the process creating other problems. Incorrect balances or levels can lead to minor problems such as algae growth or more serious conditions such as unsanitary conditions.
An example of the complexity and inconvenience of pool maintenance is seen in the regular need to "shock" swimming pools. This is required for nitrogen breakthrough, as amines (mainly ammonia) will tend to build up in a swimming pool over time and they bind with chlorine to form chloramines. It is chloramines which cause the burning of eyes. Shocking the pool water oxidizes the ammonia to nitrogen. This process is called break through. However, by shocking the pool regularly the pH tends to rise thus the pH must be lowered again and a chemical must be used to lower the pH. A similar situation occurs when metals are introduced by the source water. Chelant solutions are recommended to keep the metals in suspension from staining. However, some of these chelants are phosphate based and phosphate is a micronutrient for algae, thus encouraging algae growth. Not only do other problems occur, but also the water becomes saturated with minerals such as calcium, causing an unpleasant film on the bather.
Most solids are removed by filtering. Since filter cleaning takes considerable time and may result in problems, it is preferred to design the filter system so as to extend the length of time between cleanings. Most conventional manually-cleaned filtration systems are thus oversized to extend the amount of time between cleanings. There is a need for a system which permits use of smaller, more optimum, filter sizes, yet which can be used for extended period prior to cleaning.
There is thus a need for a new water purification system that would reduce maintenance labor and chemical costs for maintaining ponds, fountains, hot tubs and swimming pools.