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Finding the right fan and filter

Posted by Jesse Wooster on


It is important to have the air flow correct as it helps to control temperature, which is one of the key factors in plant health. We have a handy formula (attached below) for you to use to ensure you are making the right decision for your space. You need to make sure you are moving enough air to make it through the heat of summer, and you want a fan that will give you the ability to control your airflow and win the war against temperature fluctuations.

Don’t worry, here at The Grow Bro’s we pride ourselves on giving the best information possible to help you set up the ideal growing environment.

Having proper circulation in your grow tent is essential to preventing mold and powdery mildew from growing. Here at The Grow Bro’s we can assist you in determining the proper size fan for your needs

Using an inline fan is also a great way to replace CO2 inside your tent. When your plants reach a decent size they’ll start to consume a considerable portion of the available CO2 in your grow space. One method to avoid that is by pumping out the old air and replacing it with new air.

When you’re replacing air in a grow space, the general rule of thumb is being able to replace all of the air once per minute.

Then you need to make a few additional considerations, such as 25% fan power reduction if you add a carbon filter, and 30% power reduction for each 90 degree bend in your ducting.

There are two options for placement of your fan. Either inside or outside. What’s the difference? If you choose outside, the fan will pull air from the inside of your tent to the outside, via a duct on the top corner of your tent.

If you choose inside, you’ll want the fan and filter (if you use a filter) hanging in the top area of the tent where the hottest air naturally flows to. You’ll need hangers to hang your fan and filter from the inside ceiling. Not all fans include hangers, so make sure you’ve got them. 

If you ask me I think hanging inside the tent is easiest. If you put the fan outside, you’ll need to find a way to make it rest in a good position. 

The bottom generally has passive air intakes – netted windows or vent holes allowing new air to flow into the tent. The new air gets pulled in naturally as the fan creates a low pressure environment inside the tent as air gets pumped out. 

The setup is fairly simple provided you have the necessary parts. Just make sure you have the proper size ducting (same diameter as your fan), duct clamps (usually included with ducting), hangers for hanging, and zip ties (make sure zip ties are long enough to go around the diameter of your carbon filter). 

The carbon filter is optional, but it’s highly recommend it if you don’t want the smell of the plants traveling beyond your grow tent. 

To set up the filter, simply connect ducting to the side of your fan that sucks in air. Connect the other side of that duct to your filter. Secure both sides with a clamp (usually provided). 

How to install a grow tent fan & carbon filter inside your tent: 

  1. Attach & adjust hangers: 

Attach the hangers along the support bars of your grow tent ceiling. You’ll need enough for the fan and ducting. Adjust them to the length you’ll be hanging the fan. Remember hot air stays at the top of the tent so don’t hang too low. 

      2. Attach zip ties: 

Place zip ties or metal brackets on the attachment area of your grow tent fan. Connect zip ties to hangers. 

     3. Connect ducting: 

Connect ducting to the output side of your grow tent fan, wrap zip ties or metal brackets around ducting and connect to hangers. 

     4. Connect carbon filter: 

Connect your carbon filter to the intake side of your grow tent fan (the side that sucks air in). Use provided clamp or zip tie. You can connect it directly to the fan, or use ducting in between. 

     5. Run ducting through tent exhaust opening: 

Run the ducting through the opening in the top of your grow tent. Secure the grow tent duct sleeve tightly around the fan ducting