I just use my built in tank flush.. Make sure my tank is At least 3/4 full before I dump. Turn on tank flush, pull black valve. Using clear elbow, watching for 'clear' water.. Close valve leaving tank flush on, go into trailer and watch tank level. When it gets to 2/3 full go back outside and pull valve open.. I do this 3 or 4 times. Never had issues with smells from tanks.
Just don't get sidetracked when the valve is closed and tank flush is on..
TT: 2015 Jayco Jayflight 26BH Elite
TV: 2014 Ram 1500 Sport, 5.7 HEMI 3.21, Firestone 1000# air suspension. WD hitch w/800# bars
SOLD: 2012 Jayco J-series 1007