thanks kindly Ryan... Boston was a truly wonderful time/club.
As per your salinity concerns... 'twas answered/addressed earlier in the thread:
"Now you may be wondering... isn't that slight overun (<1/2" over float switch level) adding a little bit of salt to the tank and increasing my salinity slowly over time? Well... theoretically yes. But if you will worry about that, then are you also calculating the similarly lost salt due to salt creep? Heehe... point is, either way its a small amount of salt. And either way, with or without salt added or exported (creep)... you still need to make slight corrections over time to the tank by checking salinity. If its a big deal (large sump)... you can compensate then by making your new seawater used for auto-water changes just slightly less saline."
Indeed... without a WCD, your salinity can/will still change and stray over time through various habits (kalk dosing, salt creep, misadjustments on make up water, etc). We are always and often using our hydrometers/refractometers for various things. So for the huge time savings and benefits of a WCD... the occasional check and tweak of salinity is a small matter.