Relax SPA Brominating (Bromine) Granules 500g. Relax Spa/Hot Tub Brominating (Bromine) Granules 500g. Dose as a rate of 3g per 1,000 litres to boost bromine by 1ppm. Re-test your hot tub water and repeat dosage until Bromine reading is between 4ppm and 6ppm.
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