Fill "u-bend" with cold water to the approximate level marks and fit to your grommet or rubber bung. When fermenter is correctly sealed the water should no longer sit "level" in the airlock but should be pushed higher on one side than the other. The water should remain "uneven" through out the whole fermentation.
If sitting level the fermenter is unlikely to be sealed correctly and the CO2 gas will not push bubbles out through the airlock water. Please contact us. NB: Plastic top with holes allows gas to escape but stops fruit flies from making it into the water in the u-bend.
Remove cap to add water initially. Maximum Temperature: 60 °C (140 °F).