Cleaning Protocol

March 2018

For many years, the city used a combination of cleaning protocols that were harmful to the plants and creatures in the pools. However, with new awareness came a desire to conserve the ecology while still providing a safe, enjoyable experience for people using the facilities. 


Here is a summary of the cleaning protocols that were used in the past and the ones being deployed now:



  • The pools were drained overnight.

  • Copper sulphate was applied to the algae on the tops and sides of the walls the following day.

  • The tops and sides of the walls were scrubbed.

  • A mix of lime and copper sulphate was applied as a first coat.

  • A second coat of lime was applied.

  • This method was done on a monthly basis.



  • Lack of algae on the tops of the walls and stairs rendered them less slippery.

  • Regular “blitz” method ensured pools were continuously algae free.



  • The draining of the water, combined with the copper sulphate, killed off almost everything in the pools. 

  • Copper sulphate is toxic to both humans and animals.




  • The pools are no longer drained.

  • Algae on the tops of the walls and the stairs is scraped off using metal brushes and scrapers.

  • The side walls are no longer cleaned.

  • The tops of the walls are painted with lime wash.



  • Lack of algae on the tops of the walls and the stairs makes them less slippery.

  • Marine life is left undisturbed on the side walls.

  • The lack of draining leaves the ecosystem intact.



  • Scraping off the algae is not completely effective and because it takes so long, it often leaves insufficient time for the application of the lime wash between tid






The main hurdle with the new cleaning protocol is the length of time it takes to manually scrape the algae off the tops of the walls and stairs and the efficacy of this method. In striving to find a long-term solution that will ensure enjoyment for those who use the pool, while protecting the marine life within them, we are testing various high-pressure hoses.


We have found one that uses seawater from the pool and quickly blasts off all the algae – even stubborn layers the scrapers had been unable to remove. The efficiency of the power-blasting leaves more time for the application and drying of the lime wash. This in turn reduces the amount of lime wash bleeding into the water and enhances the efficacy of the lime wash in removing the algae.

A summary from the City of Cape Town regarding the cleaning protocol


On 28 February 2018, Gregg Oelofse <> wrote:

Dear All


In the last three days we have received hundreds of emails split between those that want completely cleaned tidal pools and those that want the pools left alone for nature.    We appreciate all the emails and concerns raised. The tidal pools are important recreational spaces that were built specifically for that purpose.  Overtime they have also become a natural part of the marine inter tidal zone.  The City no longer endorses the wholesale use of chemical products to clean tidal pools for the exact reason of avoiding and preventing negative impacts on our marine environment.  However we also need to ensure that where possible walking surfaces that people use to access the tidal pools are cleaned to reduce the risk that they pose to users particularly slipping and falling.  We have had a number of people that have reported falling or slipping in recent months.    


Internally we have developed a cleaning protocol to work towards a set standard of social and environmental care that looks to meet both the needs of the users and their safety as well as our marine environment. We are not of the view that our approach to tidal pools and their maintenance must be all about the environment or all about safety of users, but rather a healthy balance of meeting the needs of people and protecting our environmental resources.


In this regard  chemicals are no longer used at the tidal pools but lime washing/painting of the top surface of some of the walls, steps and platforms is required.  Marine growth is prolific and scraping the growth off only allows it to grow back immediately.    Lime washing reduces this growth rate and keeps the surface area safer for walking for longer. If managed correctly and timed with spring low tides this lime washing/painting of surfaces will have very little impact on the marine life in and around the pools.  On a pool by pool basis it will be determined which surfaces will be treated or left based on how each pool is used or accessed.


Some side walls were apparently lime washed yesterday and the contractor has been asked to revise his work to comply with the above.  We will continue to amend and update the protocol to continuously work towards the best outcome for all aspects of the tidal pools so that they can be sued for recreation and retain their marine biodiversity             


Best wishes



Gregg Oelofse

Manager: Coastal Management


7th Floor, 44 Wale Street

Cape Town, 8000


T        + 27 21 487 2239

F        + 27 21 424 9897

M      +27 83 940 8143