Every 2-3 weeks, it's recommended to check the stones in the water by tapping the container to see if the stones produce any bubbles after 30 minutes of sitting. If the bubbles are absent, then the stones should be cleansed as follows:
1. Fill the container with Bio-Q with 1 litre of water.
2. Add a teaspoon of vinegar into it and gently shake the content.
3. Leave overnight for the vinegar to effect cleansing action on the stones.
4. Rinse the stones the next day and they are as good as new.

Effectiveness from the date of first application:

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