Wait until it is more than 1/2 full before flushing. use PLENTY of water during the flush if you can, after it is empty, fill it at least to the previous full point and drain it again. Make sure you put a gallon or so back when done so your poop won't stick to the bottom of the tank
__________________ 2014 Georgetown XL 352QS 2013-2019 Days Camped-502
iNVEST IN A CLEAR ELBOW......you'll be able to see the results....and stay there while using flush.......some have walked away and forgot it was on......not good! lol......when done flushing and valve closed, you can add a little water to tank using the flush......