Best black water holding tank bacteria solution?

[DrivingMissLazy]

Gumpy, You just reminded me of what my problem was. It was the overflow in the toilet itself. I finally plugged it with silicone and my problem went away.
There is a vacuum created by the front window which is shown by curtains pulling out the window when driving and the window is open the least bit. 
Thanks for reminding me so I can put it in the new hints board.
Richard

[NJT5047]

I haven't treated the tanks with anything. I really don't think you should have to, but I may end up doing so.
Will try that for this summer.

Try a little tank treatment and you'll probably resolve your problem.   After 30 plus years of trying different ways to handle this issue, and forgetting to treat the tanks occasionally, BIG MIStake,  I wouldn't do without it.   I can walk through a campground and very quickly locate the "greens" RVs.   
Doesn't Ridex have to 'cook for a while to get a good colony growing before it works?    Have to look at that sometime.  But in the meantime RV products work too well, and most don't have formaldyhde (spelling?) and so don't harm the environment.   With RV tanks treatment, you can dump the blackwater right in your front yard and no one will know what it is.....maybe.  If they don't get to close they won't.  Smell won't be a problem. 
Now there may be a difference in the short term (the way I use mine) and the long term users.  I don't know. 
But, if you got odors coming into the coach when driving, it's pullng, or pumping into the coach.  Which would indicate a dry trap, or pottie seal that's leaking, or pottie flange that's leaking. 
May I ask what it is about RV black and grey tank treatment that is problematic?   I freak when it gets low...like to keep a small stash of the pottie stuff.  I have a 55 gallon tank of caca and that would be a lot of methane without something to inhibit the process.
JR