KurtG wrote:

btw, it also drive me nuts when the recommendation is to "replace your
evaporated water first" then do a water change. You want to suck out
waste water at it's highest concentrations and then refill will both
salt and fresh water to get you back to your SG.

And I'm the opposite. I mix up my salt water to the correct SG, drain my tank
down to a specific point on the glass (ie. 25 gallons low), and add the new
water to top it back off. If the water level in the tank is low before the
change, I won't actually be draining off 25 gallons, and the SG will be a bit
high after the water change. It could get quite high after several water changes.

George Patterson
If you torture the data long enough, eventually it will confess
to anything.