howze01
NJRC Member
Let me try to help everyone out here a little. What Sid is trying to tell you is that salinity will read differently at different temperatures. Unless you're using a refractometer that compensates for the temp. So, if the water your adding is a different temp than your DT but has the same reading on your hydrometer, it probably isn't the same. Your water change water should be the same temp as your DT. I have a little 50w heater that I run in my WC water for a few hours before I test the salinity (even though I use a temp. correcting refractometer). That way I get the same salinity readings. Also if your WC water is a different temp it can cause temp swings in your tank.