well this is a stupid question but my water level is low and i dont like it when you can see the water line but my salinity is 1.025 and i want to keep it that way do i add RO water or saltwater to top it off? sorry for the stupid question
If your just topping off the RO water shouldn't really change your salinity. As your tank level drops your salinity level is rising. Topping it back off to the original level should bring your salinity back to the original level. So if it was 1.025 with 55 gal in it and it evaporates 1 gallon of water and you add 1 gallon of RO water you should still have a salinity of 1.025 when your done. The small amount to prevent from seeing the line in the tank shouldnt change your salinity level at all really.