Mars Hydro 15L Ultrasonic Cool Mist Plant Humidifier

The Mars Hydro 15L Ultrasonic Humidifier is a high capacity cool mist humidifier designed for grow tents, plant rooms, greenhouses, and other indoor growing spaces that require stable humidity over longer periods.

With a 15L top fill tank, maximum mist output of 1.6L per hour, and coverage rated up to 861 ft², the unit is built for larger spaces where smaller tabletop humidifiers require constant refilling.

A wired temperature and humidity sensor continuously monitors the surrounding environment, while the built in humidistat can automatically pause humidification once the selected relative humidity level is reached. Four mist output levels, a 1 to 12 hour timer, remote control, flexible distribution hoses, and multiple nozzle configurations give growers control over both how much moisture is produced and where it is delivered.

Mars Hydro rates maximum runtime at approximately 29 hours, depending on selected mist output and environmental conditions.

• 15L top fill water tank
• Up to 1.6L/hr mist output across 4 levels
• Coverage up to 861 ft²
• Automatic humidistat, 1–12 hour timer, and remote control

15L High Capacity Water Tank

The humidifier uses a 15 liter reservoir, reducing the need for frequent refilling during extended operation. The top fill design allows water to be added directly through the upper tank opening without removing the entire reservoir from the machine.

Mars Hydro recommends maintaining the water level within the designated range and specifically advises using distilled water to reduce mineral deposits inside the humidifier.

Up to 1.6L/hr Mist Output

Maximum humidification output is approximately 1.6 liters per hour. The humidifier offers four selectable mist levels:

• Level 1: 0.51L/hr
• Level 2: 0.66L/hr
• Level 3: 1.23L/hr
• Level 4: 1.60L/hr

This allows growers to reduce output for smaller spaces or lower humidity requirements and increase output when faster moisture delivery is needed.

Up to 861 ft² Coverage

Mars Hydro rates the unit for spaces up to approximately 861 square feet. Actual performance will depend on room volume, ventilation, temperature, existing humidity, and how frequently air is exchanged.

For grow tent applications, the included hose system can route mist directly into the enclosure while the main humidifier remains positioned outside or beside the tent.

Automatic Humidity Control

The built in humidistat allows target humidity to be set from 35% to 95% RH in 5% increments. Once the selected humidity level is reached, the humidifier automatically pauses mist production, resuming when humidity drops below the target.

This creates a more stable environment than simply running the humidifier continuously at one fixed output. Mars Hydro lists 14 selectable humidity levels across the 35% to 95% range.

Wired Temperature and Humidity Sensor

The included wired probe measures environmental conditions away from the humidifier itself. This can provide a more representative reading of the actual growing area, particularly when the humidifier is positioned outside a tent and mist is delivered through a hose.

The display automatically alternates between temperature and timer information while also showing the measured humidity level.

Temperature and Humidity Calibration

The sensor readings can be calibrated when required. Mars Hydro allows both temperature and humidity calibration adjustments to be entered and permanently saved.

This is useful when comparing the humidifier's sensor against a trusted reference instrument and compensating for a consistent difference between readings.

Four Mist Levels

Rather than operating only at minimum or maximum output, the humidifier provides four distinct mist settings, giving growers more flexibility when environmental demand changes through the day or when the same unit is used across spaces of different sizes.

The humidifier defaults to Mist Level 4 when started unless previous settings are restored through the memory function.

Up to 29 Hours of Runtime

Mars Hydro lists a maximum runtime of approximately 29 hours. Actual runtime depends on the selected mist level and whether the humidistat is cycling the unit on and off.

At lower mist output or when the room frequently reaches its target humidity, the large tank can reduce how often the system needs attention.

Flexible Mist Distribution

The humidifier includes multiple hoses and nozzles so mist can be directed where it is needed instead of simply rising from the top of the machine. Included accessories support several different configurations for plant rooms and grow tents.

The manual shows long and short telescopic hoses, straight sections, multiple directional nozzles, and multi outlet fittings that can distribute mist toward more than one area.

Telescopic Hose System

The long telescopic hose can extend from approximately 15.75" to 61.81", while the shorter hose sections provide additional routing flexibility.

Mars Hydro recommends avoiding sharp bends, including U shaped or O shaped hose routing, because condensed water can collect inside the hose and potentially cause leakage.

Multi Tent and Plant Room Setup

The included hose and nozzle system makes the humidifier adaptable to several layouts, including directly inside a plant room, beside a grow tent with the hose routed inside, across multiple areas using split nozzle configurations, or with elevated mist outlets for improved distribution.

Mars Hydro's manual illustrates dedicated layouts for both planting rooms and grow tents.

1 to 12 Hour Timer

The humidifier includes a programmable timer adjustable from 1 to 12 hours in one hour increments. When the selected timer period expires, the humidifier automatically shuts down.

The timer can also be disabled when continuous humidistat based operation is preferred.

Remote Control

A remote control is included for adjusting major functions without using the front panel. This is particularly useful when the humidifier is positioned outside a grow tent or in a location where direct access is inconvenient.

Major settings can be adjusted from either the touch controls or the remote.

Screen Sleep Mode

The display automatically dims after approximately 30 seconds of inactivity while the humidifier continues operating. A dedicated screen off function can also immediately darken the display.

This helps reduce unnecessary light inside growing environments during dark periods while maintaining humidity control.

Memory Function

The humidifier remembers previously selected operating settings after restart, including mist level, timer, and humidity target. This reduces the need to completely reprogram the humidifier after each power cycle.

Automatic Low Water Protection

The humidifier monitors water level during operation. If the water level remains below minimum for approximately 30 seconds, the warning indicator flashes and an alarm sounds before the humidifier automatically shuts down.

This prevents the ultrasonic system from continuing to operate without sufficient water.

Quiet Ultrasonic Operation

Mars Hydro rates operating noise below 40 dB(A). The ultrasonic vaporizer produces cool mist without the heating elements used in warm mist humidifiers, making the unit suitable for indoor environments where noise and additional heat should be minimized.

Mobile Four Wheel Design

The humidifier is designed for easier movement between rooms or growing areas. Its tall floor standing body sits on a wheeled base, helping operators reposition the full size 15L unit without lifting it each time.

This is especially useful when the humidifier is shared between several tents or plant areas.

Cleaning and Water Quality

Mars Hydro recommends using distilled water to minimize mineral buildup and cleaning the unit at least weekly. The manual recommends a 1:1 mixture of water and white vinegar or citric acid, soaked for at least 10 minutes before cleaning the tank, sink, base, atomizer, and air inlet screen.

Stale water should also be replaced regularly, and the tank should be emptied completely before long term storage.

What's Included

• Mars Hydro 15L Ultrasonic Humidifier
• Remote control
• Wired temperature and humidity sensor probe
• 2 long flexible telescopic hoses
• 4 short flexible telescopic hoses
• Long straight pipe
• 4 short straight pipes
• 2 way nozzle
• 3 way nozzle
• 4 way nozzle
• Quad directional nozzle
• Cleaning and fixing kit
• 3 Velcro straps