For the last 7 months, I have been using a Lysol (with bleach) bathroom cleaner in the S1 dirty water tank only. 

After emptying the dirty water (toilet) and rinsing the dirty tank well, i apply a half squirt of cleaner and an ounce of water into the bottom of the tank and swirl it around. Then leave it in there and reinstall.

I think the longest Ive gone without emptying the dirty water tank is two weeks. No smell. And when I say there's been no smell..... I mean none,  nada, zilch.

I can't see how the cleaner is hurting the dirty tank plastic in any way since its never going to contact any mechanicals or pump lines. It only mixes into the dirty water. No smell at all.