Hygrometer & Thermometer for Standard Monotub

The Hygrometer & Thermometer for Standard Monotub is a compact digital instrument that lives inside your tub and continuously measures both relative humidity (RH) and temperature — with a one-button toggle between °C and °F. The sensor head sits flush in a 2" (51 mm) hole, while the LCD display stays on the outside, so you can read your microclimate without lifting the lid and disturbing the fruiting environment.

Why measure RH and temperature?

A monotub is essentially a controlled mini-climate. The difference between a tub that pins evenly and one that aborts often comes down to a few degrees Celsius or 10 % RH. With a built-in hygrometer and thermometer you can:

• Confirm colonisation conditions (warm, stable, high CO₂) before introducing fresh air.
• Verify fruiting conditions (cooler, lower CO₂, 90 %+ RH) after switching to filter exchange.
• Catch sudden drops in humidity that lead to dry casing layers and aborted pins.
• Spot temperature swings from heating, sunlight or draughts in your grow room.

How it fits the monotub ecosystem

This unit is designed for the same 2" (51 mm) holes that hold our Standard Monotub Filters and hole plugs. A typical setup uses one hygrometer/thermometer position plus filter and plug positions, so you can swap between phases without ever drilling a new hole:

• Colonisation phase — block all 2" holes with silicone hole plugs to trap CO₂; keep the hygrometer/thermometer in place to monitor temperature.
• Fruiting phase — replace plugs with self-adhesive 65 mm Standard filters for passive gas exchange; the hygrometer/thermometer now confirms that humidity stays in the 90 %+ band.

Specifications

• Type: digital hygrometer + thermometer, snap-in mount
• Mounting hole: 2" (51 mm) — fits a standard monotub
• Display: LCD, mounts on the outside of the tub
• Measures: relative humidity (%RH) and temperature
• Temperature units: switchable between °C and °F
• Use case: indoor monotub cultivation, colonisation & fruiting

Need the matching hole or plug?

To make a clean 2" (51 mm) hole in your tub lid, use our matching hole saw. To temporarily seal that hole during colonisation, use our silicone hole plugs. To exchange air during fruiting, use our self-adhesive Standard filters.

Hole Saw for Standard Monotub

Hole Plugs for Standard Monotubs — 6-Pack

Standard Monotub Filters 65 mm — Self-Adhesive 12-Pack