Summarize the following:
When water evaporates, it leaves the salt behind in your tank and it will increase your salinity. Use fresh distilled water that has been heated to the temperature of your aquarium to replace any lost water. Mark the tank at the top where the water level should be so you know how much water to add back in. Water needs to be changed and replaced every 2 weeks to remove filth and chemicals. Use a water siphon to remove 20% of the water from your tank and replace it with the same amount of heated saltwater. Alternatively, clean the tank weekly by removing 10% of the water once per week. When you’re mixing saltwater for a water change, make sure your solution has the same salinity as your tank. A stronger or weaker solution will raise or lower your tank’s salinity respectively. Mix and heat a saltwater solution 1 day before you perform a water change on your tank. Over time, salt deposits will form on the sides of your tank. The salt is removed from your water and will lower your salinity. Add a saltwater solution to your tank to raise the salinity back to the levels you need for your tank.

Summary:
Top off evaporated water with fresh water if the salinity is too high. Change 20% of the water every 2 weeks. Match the salinity of new saltwater with your aquarium. Compensate for salt creep by adding saltwater solution to the tank.