i figured since i paid my dues, may as well show why. this is my 2nd 180, because my first 1 broke. my sump is in the garage. the top sump on the shelf is for my ro\di water. the filter is right by the washing machiine, so i pump the waste water in there. works good, since i make up 10 gallons at a time, it fills washer for a load. laffin the bottom sump on the shelf is for my top off water, it drains into the sump with a float valve. i drain ro water into a 5 gallon bucket, make salt or top off water, which ever i need, then pump top off water in to the bottom sump