> For the complete documentation index, see [llms.txt](https://faq.growsensor.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://faq.growsensor.co/substrate-probes/my-vwc-reading-is-too-low-or-high-help.md).
# My VWC reading is too low or high, help!
Proper positioning is key to obtaining accurate and reliable moisture measurements.
### **VWC reading too low**
#### Possible cause:
* The sensor is placed too high in the substrate, causing it to underestimate moisture levels.
* The sensor's electrical current does not fully propagate through the substrate, leading to lower-than-expected readings.
#### Solution:
* Reposition the sensor lower in the substrate, closer to the root zone, to capture a more accurate moisture reading.
### **VWC reading too high**
#### Possible cause:
* The sensor is placed too low, near the bottom of the substrate, where excess water can pool.
* The electrical current extends into the saturated zone, inflating moisture readings.
#### Solution:
* Move the sensor slightly higher to avoid detecting pooled water at the bottom.
### **Substrate-specific placement adjustments**
* Coco coir retains water differently than rockwool, often leading to a higher saturation zone near the bottom.
* To compensate, position the sensor one inch higher in coco than you would in rockwool to achieve more consistent and accurate VWC readings.
By adjusting sensor placement based on your substrate type and root zone conditions, you’ll ensure accurate, repeatable moisture measurements, leading to better irrigation decisions and healthier plants.
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