JennaBee,
It seems that you are saying that the water level in the main tank won't fill all the way up to the top...which is normal. It will only fill as high as your drain/overflow will let it...then it flows down to your sump where your return pump sends it back up to your main tank. Like David said...posting details will help a little. As David said, to bring your salinity down, you must remove salt water and replace it with fresh water. How far off is your salinity?
R, Jamie
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