That sulfur smell after a monsoon is almost always the tank charge getting watered down, not a reaction with the deodorizer. Rain sneaks in through the roof vent and the gaps around the door and roof seam, and on a weekly schedule that extra water thins out the blue chemical in the holding tank. Once it's weak, the bacteria in the waste take over and put out hydrogen sulfide, which is the rotten egg part. The liquid can still look blue and normal while doing a lot less.
The other half is the air. Right after a storm it's humid and still, so the vent pipe stops pulling and the gas just hangs inside the cabin instead of drafting out the top.
What fixed it on our sites during storm season:
- Call for an extra chemical drop after any heavy rain instead of waiting for service day. Our driver would add a recharge without a full pump when the tank wasn't close to full.
- Have them check the vent cap and the roof for cracks. A missing cap lets in way more water than you'd think.
- Turn the unit so the door faces away from the storm wind.
- Prop the door open for an hour once the rain stops to air it out.
If it still stinks two days after a storm, the tank needs a full pump and recharge, not just a top off.
