Got'er done! Drilled a 1 3/4 in. hole, looked inside of tank, and it was NASTY. Sand and suspended nasties and gunk floating on the top of water...and the smell... Wet/dry shop vac with attachements, and sucked it up. Also was able to get the plastic pieces that was clogging the drain tube. An adjustable high pressure sprayer on end of garden hose to rinse inside of tank. Rinse and vac 6 times till I was satisfied. Added some water, then the half gal of bleach, added more water till tank was just over half full. Drove MH around town taking corners and stops to slosh the mixture around. Ran water thru all the lines of MH {I by-passed water heater}. Opened drain valve on the drive home. My drive way slopes just right for draining tank and having drilled hole in tank where I did, maximized vacumming water out of tank. Rinsed inside tank one more time, flushing water lines, and plugged the hole I drilled with...a hub oil cap that fits on the axle of a semi trailer! THANKS to the guys at the truck shop! Rubber cap fits snugg , flush and looks damned near professional!