Ok,
You need to do you makeup water ( salt water ) out of the tank... meaning in a seperate container.
That is very very low, your fish won't last long in there. Make up 10 gallons of 2.00 salinity water and then do a water change. As you are adding the new high salinity water check the tank water and add it slowly! When you get the salinity up to 1.023 in the tank finish the water change with fresh Ro ( no salt added ).
Are you sure you are reading you hydrometer right? Just to clarify one point - Don't add salt directly to the tank!!!