G.A.S Intelligent Humidity Controller

• Relative Humidty 24 hours

It'll maintain your chosen relative humdity 24 hours a day

• Relative Humidity Day / Nght

This maintains your chosen relative humdity, with one setting for day (lights on) and another for night (lights off) .

• VPD 24 hours

This calculates your VPD - the 'drying power' of air - based on: air temperature, relative humidity & plant temperature. You will need to specify the stage of growth you're at, and enter a target VPD for each stage of growth. Your ideal humidity is calculated and maintained, based on this. 

• VPD Day / Night

During the day, the controller works as described in 'VPD 24 Hours'. During the night, instead of targetting VPD, your controller monitors & maintains a static relative humidiity. This is because plants don't photosynthesise and don't need to transpire at night. Instead, it's more important to keep your relative humidity low, to prevent mould.

We recommend going for: VPD Day / Night. 

Plants constantly transpire - this is where they lose water. This process directly impacts nutrient uptake, translocation & ultimately growth. 

To control transpiration, some growers focus on their humidity. A higher humidity slows it down, a lower humidity speeds it up. The problem is, at different temperatures, your humidity has a different affect on transpiration,.

To really know how your humidity affects transpiration, you need to monitor your VPD (vapour pressure deficit).

Think of your VPD as the drying power of air. It uses your temperature & humdity (%RH) to calculate the transpiration pressure placed on plants. 

• A high VPD means the air is dry, so water leaves plants at a faster rate
• A low VPD means the air is moist, so water leaves plants at a slower rate
  
  

Remember, moisture moves from wetter areas to drier areas. The bigger the gap, the faster this happens. Kind of like how a drier sponge takes less time to soak up a spill then a damp one. 

Early Veg: 0.4 - 08 Kpa
Plants are young and don't have a strong root system to replace water lost through leaves - you want a higher VPD to slow transpiration. 

Early Flowering: 0.8 - 1.2 Kpa
Plants have more leaves and more roots, so you can go slightly lower your VPD to speed up transpiration.

Late Flowering: 1.2 - 1.6 KpA
At this point, plants are well established. Extra water uptake is helpful, and a drier air temperature helps ward off pathogens and diseases (e.g. bud rot). 

This controller is designed for use with the G.A.S SonicAir Pro Humidifer.

Place it in the centre of your grow room, above the canopy, under any lights (the probe will need to sense whether they're on or off for day/night mode).

Connect the controller to your humidifier using the male/male lead (included). 

Plug your humidifier into a socket - the controller is powered by the humidifier.

Everything is set using the large 'Menu' dial.

• Turn to the right to select menus and change values
• Press to select or open menus

When you first turn the controller on, you will be on the home screen:

1 Turn the controller to the right to show default settings

2. Press the dial to open the main menu

3. Turn the dial to move through menu items

4. Select items from the menu by pressing the dial

The probe comes pre-calibrated, however you can recalibrate it to offset the temperature or humidity. 

To do this, enter the main menu, scroll to 'probe calibrate' and select it.

There's an option to enter a 'leaf temperature offset'. This is how much lower your leaf temperature is than your grow room temperature. We recommend an offset of '-1' for small plants, or '-2' for bigger plants.