My tank is 125 gallons and 6 months old and every time my water evaporates I add fresh water. When I do water changes im trying to get salinity up again and it takes me a bit to get it to the right number, in the beginning I was using red sea coral pro salt now when I told the store owner what i was using he said not to use that brand cause it would raise my alkalinity levels. So now im trying to figure out what brand of salt to use for my tank.