NEVER mix different products together in the same bottle, pail, or similar container. Adjust pH of spa water to the range of 7.2-7.6. If spa is freshly filled and before initially using this product in the spa or hot tub add sodium bromide, according to the label's instructions, to introduce a bromine residual of 2-4 ppm. Check feeder regularly to ensure that this product is continuously introducing bromine to the water. When empty or when levels are low, add additional product as necessary to maintain a bromine residual. To ensure sparkling clean water and that your spa chemicals work effectively, water in spas should be changed every 60-90 days. Commercial spas should have the water changed every 3 to 5 days. Do not re-enter spa or hot tub until bromine residual is 4 ppm or less as determined by a bromine test kit.