Green water is generally caused by Phosphate levels in the pool exceeding the amount of sanitisation in the water

Phosphates are algae nutrients but are hard to break down and can enter the water through the following :

  1. Decaying plant matter (eg Leaves)
  2. Fertilizer drift
  3. Metal treatment compounds (water boards or your own use)
  4. Groundwater run-off
  5. Bird Droppings
  6. Bather wastes (eg Urine or sweat)

Phosphates encourage algae growth and above 0.3mg/litre can encourage Biofilm development. Furthermore combined with high calcium they encourage calcium phosphate scale formation which makes it harder to remove phosphates from the water.

Therefore, both phosphates and calcium hardness are recommended to be simultaneously controlled to effectively treat phosphates in pool water.



How to clear a Green Pool

1. Back-wash sand filter for some 2/3 minutes.
Make sure cartridge or D.E elemental filter is clean to start with .

2. With the pump running carefully pour around pool water surface ‘Surex Surchlor’ to the following specifications:-

  • 20lts to water volumes up to 45m3 (10,000 galls)
  • 40lts to water volumes up to 90m3 (20,000 galls)
  • 60lts to water volumes up to 135m3 (30,000 galls)

It is necessary to run the pool circulation continually until water clarity is achieved.

3. Add 1kg per 45m3 of water volume of Surex Minus to reduce pH levels to approx’ 7 to 7.5.

The green colour of the pool water should now change to a milky appearance, caused by the bleaching effect of the Surex Surchlor.

4. The application of a Flocculent / Clarifier is now required.
ADD: 1kg of Surex ‘Surfloc’ as per instructions on compound label
1 x 150grm L’Bloc direct into clean pump strainer basket.

Both compounds will assist with the ‘clearing process’.

5. Sand filters should be backwashed for some 2 to 3 minutes every 4/5 hours with repeated application of Surex ‘Surfloc’ at a rate of ½ kg per 45m3. There is no need to add anymore L’Bloc’s.

Within the first day of this ‘clearing procedure’ back washing the sand filter should be undertaken at least 3-4 times.

Equally ‘painful’ cleaning of cartridge or D.E. elements of accumulative debris from the bleaching of the green algae should be undertaken at least 2-3 times within the first day.

Pool water after the first 24hrs of the above treatment should start to gently clear.

6. Within the course of the next 24hrs maintain pH levels between 7 to 7.5, add ½ kg of Surex ‘ Surfloc’ per 45m3 after at least a further 2-3 backwashes. There is no need to add anymore L’Bloc.

Pool water should now start to look considerably clearer.

Carry out the above treatment preferably over a weekend this will give you more time to concentrate and be more productive on the application.

Once the pool water is clear vacuum out the accumulative sediment from the use of Surex ‘Surfloc’.

With the use of the L’Bloc no sedimentation occurs.

Prudent pool owners will find it beneficial to keep the circulation running 24hrs a day during the proper swimming pool season- less chemicalisation is required with less of a risk of the water turning green.