Out of town for 3 weeks, how to set my tank...

[Bloodasp]

I guess what he is saying is that the garbage bin you will be using will be filled with fresh water. Right now you are topping of your sump 5 galons of water every week if i read that right. The idea of an auto top-off is that you no longer need to manually top off your sump as it is done automatically. every time your water level drops from a certain level water from your reservoir is added to your sump until it reaches the point where the level originally was. This is actually good even to use even when you are around as it eliminates the fluctuation of your salinity level. And from what I understand you top off once a week, that's a huge fluctuation of your salinity level.