On occasions a spa will become infected with algae. This is more common with tank water. Should this occur we would recommend the following: Purchase a packet of Spa Fresh Algicide.
Make a premix with one half of the contents of each colour sachet in some water and when dissolved pour the blend into the spa. Try to have the pH at 6.8 -7 as this will assist the algicide to be more effective.
Circulate and filter for 8-12 hours. (The spa will initially go cloudy however do not let that worry you), turn air jets on and off several times during this time. At the same time, using a damp cloth with Spa Fresh pipe degreaser on it, wipe inside of spa and around jets, under head rests and the underside of the spa cover. Rinse off the spa cover and leave exposed to the sun.
If the infestation is severe and when the water is ready to be dumped, remove the filter cartridges, add Spa Fresh pipe degreaser and circulate for 30 minutes and then dump at this point)Burn off dead algae with Spa Fresh Spa Shock at 60grams/1000 litres and filter for 4 hours, then clean filter cartridges, thoroughly rinse and flush the filter cartridges until water runs clear through the filter cartridges. If required, balance water with Spa Fresh Balance (alkalinity 120ppm, pH 7.6.)Finally, dose the spa with Spa Fresh Spa Sanitiser at the rate of 1 litre/1000 litres of water.