Foam in spa water can be caused by one or a combination of any of the following factors:

  • Dirty filter
  • Low calcium hardness level
  • High Total Dissolved Solids (TDS)
  • High phosphate level
  • Cleaner residue


  • Rinse the hot tub cartridge and check that the pH is between 7.4 and 7.6.
  • Run the filter for 24 hours.
  • Add a shock treatment using the dose recommended for your spa’s specific volume; wait 15 minutes.
  • Add 10 ml of anti foam product per 1,000 litres of water.
  • Let the product work for about 10 minutes; repeat if foam persists.
  • Lower the alkalinity level if it’s above 150 ppm.
  • Check the spa’s calcium hardness level (ideal: 150 ppm).
  • Clean the cartridge filter with the product recommended by your Sanimarc Pro dealer.


Dirty foam in a Hot Tub or Spa can be the result of any number or combination of factors which may include an extremely dirty spa filter, bacterial/slimy coating on the walls of the hot tub, inadequate levels of sanitation, or high Total Dissolved Solids (TDS) level.


  • Add 25 g of brom product for every 1,000 litres of water. Wait 24 hours. Run the hot tub for 20 min. Wait 24 hours.
  • Add 250 ml of decalcification product for every 1,000 litres of water. Let the spa run 1 hour then drain it.
  • Refill the hot tub and start your maintenance program.