- If you do less or equal than 10 measurements a week, change filter every 6-12 months
- If you do more than 10 measurements a week, change filter every 3-6 months
- If instrument is in use, day and night, change filter every 2 months
Please read the operating instruction manual of the water activity meter as well to learn about the procedure how to find out the optimal chemical filter changing interval. It is important that the filter is changed from time to time as it is of saturation type. Once saturated, volatiles will pass through and harm the sensor. Be aware that sometimes filter combinations must be used to get highest protection efficiency. As soon as ethanol is involved, our alcohol-resilient sensor (CM-3 or awSens-ELS) must be used. If ethanol is present in conjunction with other volatiles, select the alcohol-resilient sensor plus the respective filter(s) from the selection list. Note that chemical filters will extend the measurement time as the water vapor has to pass through the filter but it will not affect the measurement value. If you have doubts about the procedure or feel unsure how to work that out, please do not hesitate to contact us.
Calibration standards are reusable with a shelf life of 2-4 years, depending on factors such as storage conditions (storage container must be closed properly), frequency of use, exposure to light, and the value of the standard.