Odo-Ban!! We have never had odor problems but that is a dandy idea to keep in mind. Well, I say "never", but this doesn't count the times we've fixed something fishy for dinner and the water went into the grey tank. Ooh, nasty. But for those times, I now just use the lemony grey tank treatment. Odo-Ban fixes a multitude of things...can't believe I never thought of it for either the ROO or Rocky. Thanks for mentioning it.
Also, available at Sam's for a much better price. When you have a number of doggies, Odo-Ban is your BFF.