Bromine Granules can be used to effectively sanitise and disinfect your spa. Dose Rate: As an initial dose, add 27g Bromine Granules to 1 cubic metre of water. To maintain a spa at 3mg/litre or ppm, add 6.5g Bromine Granules per 1 cubic metre of water. We recommend periodic oxidisation using Oxidiser or the inital dose rate of 27g per cubic metre of water. Do not use the spa until the Bromine residual has fallen within the desired range. 3-5mg per litre or ppm.