Maintaining clear water without turbidity.
Suspended particles in the water. Coagulation/Flocculation.
Swimming pool contains dispersed (solid) particles in suspension. These particles cause the haziness of the water.
There are bigger particles that can be retained by the filter medium (sand, diatomaceous earth, cartridges, etc.) and there are smaller particles that are not filtrable.
The small particles are usually too small to be noticed by naked eye during the day light. They are mostly charged negatively on their surface; therefore, the colloids reject each other. Thus, intervention is needed to remove them. Adding coagulants (metal salts) or polyelectrolytes, or cationic polymer, will charge them positively, thus form bigger flocs that will be able to be caught by the filter.
To have clean pool water, you need to have a good circulation system. The maintenance of the pump and filter is very important. Circulation is a process of drawing water from the pool through a suction line and forcing water back to the pool through the filter and pressure/return line. Filtration removes contaminants that can promote the growth of bacteria or algae along with particles suspended in the water that can make the water cloudy. All the residue that is caught by the filter, may create biofilm that can be very dangerous and spread more bacteria in the system. This process has a major impact in the sanitation of the water and keeping the water clear. Thus, it is necessary to clean the filter regularly on a weekly basis.
Norlex Pool & Spa offers both filter and membrane cleaners that are very effective in removing dirt, mineral oils and grease along with fouling and sludge. In addition to that, Norlex Pool & Spa offer replacement filters in different materials. Please see the section under filtration here.