Diagnosis
This musty odor, often described as "sour" or "wet dog," is caused by the proliferation of anaerobic bacteria and biofilm within the Omni station's internal plumbing and the mop pads themselves. While the X2 Omni is designed to wash the pads, it does not utilize high-heat drying (like steam) or chemical sterilization. If the pads are not fully dried or if the dirty water tank (DW tank) is left stagnant, bacteria migrate from the waste tank back into the washing tray, effectively "washing" the pads with contaminated water. The smell persists because the X2's hot-air drying system may not be reaching the center of the pads if they are overly saturated or improperly seated. When moisture is trapped in the dense microfiber weave of the pads, it creates a breeding ground for mildew. You can confirm this by smelling the dirty water tank; if the tank smells, the entire internal loop of the station is likely contaminated, meaning the "clean" cycle is merely circulating a bacterial slurry over your mop pads.
How to Fix It
To eliminate the odor and reset the hygiene of your X2 Omni, follow this deep-sanitization protocol:
- Purge the Waste System: Empty the Dirty Water tank completely. Use a bottle brush to scrub the interior walls of the tank, specifically targeting the float sensor area where slime accumulates. Rinse with a mixture of warm water and a drop of dish soap.
- Sanitize the Base Tray: Remove the mop pads. Use a damp cloth with a 1:10 bleach-to-water ratio to wipe the bottom of the Omni station tray, focusing on the drainage grates where hair and debris trap stagnant water.
- The Vinegar Flush: Fill the Clean Water tank with distilled water and add 30ml (approximately two tablespoons) of white distilled vinegar. Do not use concentrated floor cleaners for this step, as they can foam and trigger a "water tank error."
- Execute a Manual Wash: With the pads re-installed, trigger a "Mop Cleaning" cycle via the Ecovacs Home app. This forces the vinegar solution through the internal pumps and across the pads.
- Deep Dry: Once the wash cycle finishes, manually extend the drying time in the app settings to the maximum duration (usually 4 hours). Ensure the robot is docked firmly so the hot air vents are aligned perfectly with the pad mounts.
If That Didn't Work
- Replace the Pads: If the pads have been used for more than 3 months without a machine-wash, the biofilm may be embedded too deeply in the fibers. Replace them with genuine Ecovacs X2 Omni replacement pads (Part #X2-MOP-01) and see if the smell vanishes.
- Machine Wash the Pads: Remove the pads and wash them in a standard washing machine on a "Heavy Duty" cycle using a laundry sanitizer (like Lysol Laundry Sanitizer) and warm water. Do not use fabric softener, as this coats the fibers and reduces water absorption.
- Clean the Internal Filter: Check the small mesh filter located at the base of the clean water tank. If this is clogged with minerals or slime, the water flow is restricted, leading to incomplete washing and "wet spots" on the pads that cause odors.
- Check for Water Leakage: Inspect the bottom of the Omni station for any slow leaks. If water pools under the station, it creates a humid micro-environment that encourages mold growth even if the tanks are empty.
Heads Up
- Empty Daily: The Dirty Water tank must be emptied after every single cleaning session. Leaving dirty water for even 24 hours allows bacteria to multiply exponentially.
- Avoid Third-Party Chemicals: Never use bleach or harsh detergents inside the Clean Water tank, as this can degrade the rubber seals and pump diaphragms in the X2 Omni.
- Airflow is Key: Ensure the Omni station is placed in an open area with at least 12 inches of clearance around the vents to allow the hot-air drying system to exhaust moisture efficiently.
- Use Distilled Water: If you live in a hard-water area, use distilled water in the clean tank to prevent calcium buildup in the spray nozzles, which can lead to uneven wetting and "stink spots" on the pads.