Save over £4 off RRP with this large multipack of Spa Lite which will last you over 3 months even if you are shock dosing your spa weekly. Spa Lite is a powerful oxidiser (commonly known as a "shock treatment") with built-in clarifiers that destroy dissolved contaminants and restores sparkling spa water. Dose weekly with spa cover off - one sachet is suitable to shock a tub up to 1500 litres (330 gals). Feel free to use your tub after just 15 minutes of application.