TrolMaster WN-9 Substrate Sensor Node | VWC, EC & Temp Add-On for WCS-9

TrolMaster WN-9 Adds Another Root Zone Reading to Your WCS-9

The WN-9 is the probe half of TrolMaster's WCS-9 substrate sensor system. It measures volumetric water content, EC and temperature from one set of stainless steel spikes. The WCS-9 set already includes one node, and this is the part you add to sample more of the room. One WCS-9 display takes up to four nodes on a single daisy chain. The display shows each node's reading as well as the average across all of them. Water content reads from 0 to 100%, and EC reads from 0 to 30 mS/cm. TrolMaster says the EC reading accounts for nutrient solution salinity, which keeps both numbers dependable as feed strength changes. The node works in traditional soil and in high bulk-EC soilless media such as rockwool. A 12 ft ECS-7 daisy chain cable comes in the box to link it to the next node or the display. The package measures 6.30 × 3.39 × 3.39 in and weighs 0.66 lbs.

Why a Second Substrate Sensor Node Changes Your Irrigation Data

A single probe only reports the block it sits in. If that block runs wet from channeling or dry from a clogged dripper, the whole room gets watered on bad data. Spreading several nodes across benches gives the controller an average that is harder to fool. That matters most with Feed on Demand, where irrigation is triggered by substrate moisture instead of a timer. Readings refresh every minute and speed up to every 10 seconds during a Feed on Demand event. Setting up a new node is simple: plug it into the chain, then shake it to pair it with the display. Calibration only needs the 100% water content point taken in fully saturated media. The sensor comes pre-calibrated for rockwool, so rockwool growers can often skip that step. Update the controller's firmware before connecting, since older versions do not support the WCS-9. Aqua-X Pro and Hydro-X Pro controllers each take up to 50 displays, while Tent-X and Green-X take one.

Key Features

• 3-in-1 Probe: Water content, EC and root zone temperature come from one node with stainless steel spikes.
• Up to 4 Nodes per Display: Chain nodes together and the WCS-9 display reports each reading plus the average.
• Feed on Demand Ready: The data drives sensor-based irrigation, with 10-second updates during a watering event.
• One-Point Calibration: Only the saturated 100% point is needed, and it arrives pre-calibrated for rockwool.
• Shake to Pair: Shaking the node links it to the display, with no extra tools or menu work.

Technical Specifications