Flocculants - clear the water fast

The quickest and most effective way to clear cloudy pool water is to use Jolly Gel, but you can also use Aluminium Sulphate in liquid form.

Astral liquid flocculant

Some of the particles that enter your pool will never sink to the bottom because they are too small and light; they remain suspended in the water indefinitely

Some examples of this type of particle are bacteria and viruses, broken pieces of pollen, fungal or algae spores and the microscopic dust particles around which raindrops form

Although the filter system will eventually remove most suspended particles of this size you can accelerate their removal

If your pool water becomes cloudy, or if you have scrubbed algae or dust from the walls and floor and made it cloudy, then the best way to clarify the pool is to flocculate the water

Different flocculants work in different ways but all encourage the suspended particles to cluster together into ‘clumps’.  These ‘clumps’ sink to the bottom of the pool faster

Generally speaking application of a flocculant will clear the water overnight

Application and removal of flocculants

  • Overfill the pool by at least 75-100mm (3-4”) to allow for water lost during the Vacuum-to-Waste that follows the flocculation process
  • During this 2 hour period, thoroughly scrub the steps, sides and bottom of the pool with the pool-brush to remove algae and adhering dust/dirt
  • Switch the pump to ‘Off’
  • Mix flocculent with water in a watering can; follow the manufacturers’ instructions and don’t skimp on quantities. (We routinely use 5 litres of flocculent in a pool of 50 m3/13,000 US Gals)
  • Sprinkle the mixture evenly onto the surface of the pool
  • The water may turn very cloudy as you add the flocculent but this will disappear quickly
  • Allow the water to remain still for 12 hours or so, until there is a layer of settled sediment on the bottom - overnight is best
  • Note: - Sometimes a whitish, lumpy scum forms on the surface.  Skim this off into a bucket.  Do not try to remove the scum with a net because it will break up and you will have to wait for another 12 hours for it to sink to the bottom
  • Vacuum the sediment to ‘Waste’; not through the filter

Note: - The sediment is extremely light, not much heavier than the water, and is easily disturbed, but don’t worry if you miss some. You will have to work quickly, because you are pumping the water to waste, but not so quickly that you stir the sediment up too much

  • When most of the sediment has been removed by vacuuming, stop the pump and set the Rotary Valve to ‘Recirculate’
  • Let the pump run for 2 hours.  During this period the flocculated particles that escaped the initial vacuum to ‘Waste’ will congregate in a few places on the bottom of the pool, deposited there by the currents circulating in the pool water
  • Set the Rotary Valve to ‘Waste’, not to ‘Filter’, and vacuum the sediment away
  • Return all valves and switches to ‘Filtration
  • Check and adjust water level, Chlorine and pH.  Repeat as and when required

Note: If your pool goes cloudy frequently it’s probable that there is a good reason for it

The most likely cause is that the media within the sand-filter needs to be changed due to age - see the Water Problems section to determine the exact cause of the problem and how to rectify it 

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Ken Walker - MyPoolGuru©