I agree with Micah. I have noticed pieces of "salt" when I premix my water, I thinkk, sometimes, it is extras in the salt mix and really should be taken out or not put into your tank. Since you are mixing the SW
in your tank, whatever doesn't dissolve, I would suck out. I have also noticed my hydormeter did not give me accurate readings when the water was cold. I have switched to a Portable Refractometer
and love the ease with which I can test my water.