TrolMaster Legacy Day/Night Humidity Controller

The TrolMaster Legacy Day/Night Humidity Controller (BETA-6) is a standalone plug-in humidity controller designed for indoor grow rooms. It uses a precision 16-foot remote probe to read ambient humidity, then switches a connected humidifier or dehumidifier on and off to hit your target. A built-in photocell detects light levels automatically, so the unit shifts between your day humidity setpoint and your night humidity setpoint without any additional timers or wiring. Humidity setpoints are adjustable across 20–90% rH.

TrolMaster Legacy Day/Night Humidity Controller Specifications

Specifications are sourced from the manufacturer’s product description for the BETA-6. Attributes not published by the manufacturer are marked (unverified).

Why Choose the TrolMaster Legacy Day/Night Humidity Controller

The BETA-6 addresses a specific gap in grow-room automation: most budget humidity controllers hold a single setpoint around the clock, but plants and their environments have genuinely different humidity needs during the light period versus the dark period. Transpiration rates change, temperature drops, and the risk of mold or powdery mildew shifts when lights go off. The BETA-6 lets you program two independent targets and delegates the switching decision to its built-in photocell rather than requiring you to wire a separate timer or reprogram a controller every time your light schedule changes.

• Separate day and night setpoints: Program one rH target for the light-on period and a different target for lights-off — the photocell handles the transition automatically.
• 16-foot remote probe: The sensor sits at canopy level or wherever humidity matters most in your space, keeping the controller unit out of the wet zone.
• Wide adjustment range: 20–90% rH covers seedling propagation through late-flower, so one controller works across growth stages without replacement.
• Simple plug-in setup: Plug the BETA-6 into a standard 110V outlet, plug your humidity device into the outlet on the bottom of the unit, and you’re operational.
• Works with either device type: You can use the BETA-6 to run a humidifier during propagation or swap in a dehumidifier during late flower — no mode switch required beyond changing which device is plugged in.

Best Uses for the TrolMaster Legacy Day/Night Humidity Controller

The BETA-6 fits grow rooms where day/night humidity swings are a routine problem and a simple, dedicated controller is preferred over a full climate automation system.

• Indoor flowering rooms: Late-stage cannabis and other flowering crops benefit from lower humidity at night to reduce botrytis risk. Set a higher daytime rH for transpiration and a lower nighttime rH to keep the canopy dry between light cycles.
• Propagation tents and clone chambers: High-humidity propagation environments (70–85% rH) often need to drop back to lower levels at night or when a root zone is established. The BETA-6 manages that transition automatically.
• Vegetative growth rooms: Maintain higher humidity during the light period to support leaf development, then drop slightly at night without manual intervention.
• Single-room facilities without a full climate controller: Growers who run individual controllers for temperature, CO2, and humidity separately will find the BETA-6 integrates cleanly without requiring a central hub.
• Dehumidification control in high-transpiration rooms: During lights-on periods when multiple large plants are actively transpiring, a dehumidifier running on the BETA-6 prevents rH from climbing beyond your target ceiling.

For growers who also need to maintain accurate water chemistry, pairing the BETA-6 with properly calibrated monitoring equipment — such as an EC calibration kit for your nutrient solution — helps maintain consistent environmental and irrigation conditions across the growing cycle.

Compatibility

The BETA-6 is designed for 110V AC electrical systems standard in North American indoor growing facilities. It controls one device at a time through its single bottom-panel outlet. Any 110V humidifier or dehumidifier that accepts standard plug-in power control is compatible — the controller switches power to the device on and off based on the sensor reading, so the connected device should be one that restarts normally when power is restored (most household-style humidifiers and dehumidifiers operate this way).

The remote probe assembly is 16 feet long, which provides enough reach to position the sensor at canopy level while keeping the controller unit mounted on a wall or shelf outside of direct moisture exposure. The built-in photocell reads ambient light to determine which setpoint (day or night) is active, so the controller should be installed where it can accurately detect the room’s light and dark periods — not inside a cabinet or in a location that stays dark regardless of the room lights.

The BETA-6 is a single-outlet controller. It cannot simultaneously run both a humidifier and a dehumidifier. Growers who need bidirectional humidity control (humidifying when rH drops below a floor and dehumidifying when it rises above a ceiling) would require a more advanced controller or a dual-outlet unit.

If your grow room also uses air pumps or other environmental equipment, see our selection of Active Aqua air pumps for compatible grow room support equipment.

Usage Guidelines

Setting up the BETA-6 for typical flowering and vegetative cycles:

• Late flower (weeks 5–8): A common target is 45–55% rH during lights-on and 40–45% rH during lights-off. Set the day dial to your daytime target and the night dial lower to reduce overnight mold risk.
• Vegetation: Most growers target 55–70% rH during the light period. Night setpoints can match or drop 5–10 percentage points below the daytime setting.
• Propagation / cloning: High-humidity domes typically target 75–85% rH. Set both day and night setpoints high when cuttings are fresh; step down the night setting as roots develop.
• Placement of the probe: Hang or clip the 16-foot probe near mid-canopy rather than at ceiling level or floor level. Canopy-level humidity is what matters for disease prevention and transpiration rate, not ambient room humidity at a high or low extreme.
• Allow the photocell time to stabilize: When lights first come on or go off, there is a brief transition period. The photocell responds to the actual light level in the room, so avoid placing the unit in direct light beam paths that could cause rapid cycling at light transitions.

Sources & Further Reading