When you're ready to open the spa for the season, begin by clearing off any water and/or debris off of the cover. Once the cover is clear, clean it with a solution that is safe for the cover (check the paperwork that came with the cover) and allow it to dry. Once it has dried, you can remove and store the cover.
Once the correct water level has been reached, start up the pump and filter and it allow it to run while checking for leaks in the pump or plumbing. If there are no leaks present, continue to let the pump run for at least an hour. If there are leaks present, mark them, then turn the pump off while repairs are made.
After allowing the metal remover to circulate in the spa for at least 4-6 hours, take a water sample (approximately a foot down) to be tested. The 4 most common chemicals tested in a spa are chlorine/bromine, pH, alkalinity and calcium hardness. If you are using an alternative sanitizer, the chemicals needed for start-up will vary.
Once the water results have been determined, you may begin adjusting the chemicals. Make certain that you are following the manufacturer's directions to ensure that the chemicals are being added properly. I would recommend adjusting the calcium first then allowing at least 12 hours before adjusting the pH or alkalinity.
Once the pH and alkalinity have been adjusted, you can add the sanitizer. If you are using chlorine, you would follow the product labels and add the granules directly to the spa water. If you are using bromine, you would use Bromine Start, to establish a "reserve" before adding the bromine tablets in a floater or dispenser in the spa. Sodium bromide is typically added at a rate of 1/2 oz. per 100 gallons of water.