A Clogged Grow Tent Carbon Filter: How To Fix It?

Every grower has experienced a clogged carbon filter at some point. It results in a significantly lower exhaust airflow that might potentially run your grow tent into problems.

A clogged grow tent carbon filter might result from running a humidifier on tap water. Also, relatively high humidity could play a critical role in how fast a carbon filter will get clogged.

If you have also noticed your grow tent smell starts to be much stronger, or that you have a dramatically reduced exhaust airflow. Then this article is for you!

A clogged carbon filter is probably the most common issue new growers face when trying to maintain optimal airflow in their grow tent. This is because most people don’t know how to fix it properly or aren’t aware of all the factors that can result in a clogged filter.

3 Reasons For A Grow Tent Carbon Filter To Become Clogged

While reviewing the most known carbon filters in the market, I have seen some carbon filter brands more prone to getting clogged than others. However, the following reasons are the main issue causing a carbon filter to get clogged.

1-Tap Water In Grow Tent Humidifier

Grow tent carbon filter is being clogged due to powder produced by a humidifier running on tap water.

Using tap water in a grow tent humidifier is one of the most common mistakes I see newbie growers do. Tap water does contain a lot of minerals.

Humidifiers work by slightly heating water and turning it into a vapor that could be dispersed to raise the humidity in the air. This process results in the separation of dissolved minerals from water. As a result, an accumulation of concentrated minerals, mostly calcium, occurs.

The minerals accumulated will be visible in a powder form that you will find spread all over the grow tent. This fine powder in itself has no significant effect on the actual plant. However, it can cause serious damage to the electrical appliances that you are using inside your grow tent.

2-Very High Grow Tent Humidity

Humidity is such a critical factor to control in any grow tent. The relative humidity levels might fluctuate significantly throughout the year. In certain growing seasons, it is required to run a humidifier in order to intentionally raise the humidity to certain optimum levels. This creates a huge problem!

High humidity means a high percentage of water vapor available in the air. Water vapor fills the pores inside the filter carbon particles, preventing it from adsorping any other organic compounds like odors.

As a result, the carbon filter efficiency significantly drops and might lead to clogging.

3-Grow Tent Prefilter Catching Dust

This might sound simple at first, but there is a huge chunk of growers who have got a clogged filter as a result of prefilter issues.

Dust could enter the grow tent through its ventilation system and settle inside your prefilter causing a significant decrease in the exhaust airflow.

If you think of it for a minute, a prefilter’s purpose in the first place is to catch dust and prevent it from reaching the carbon particles inside the carbon filter. This means that a clogged prefilter is not a great issue. The pre-filter is simply doing its job.

3 Tips For Unclogging A Grow Tent Carbon Filter

1-Use Distilled Water For A Grow Tent Humidifier

As I have explained to you previously, a humidifier doesn’t go well with tap water due to its mineral content. So, make sure you are using distilled water or RO-purified water for your grow tent humidifier.

There is a critical aspect that you need to consider, which is humidifiers use a lot of water. 1.5 Gallons per day is the minimum amount of water required by a humidifier to run for a day. So, you need to secure a cheap source of purified water daily.

2-Regulate Grow Tent Humidity

The grow tent’s relative humidity should be regulated at an 80% maximum. Any increase in the grow tent humidity would expose your carbon filter to more clogging issues.

3-Grow Tent Prefilter Cleaning Schedule

Constantly cleaning your prefilter prevents the accumulation of dust and other particles in the grow tent. Prefilters are super easy to clean; all you have to do is to put them in a washing machine.

However, if the grow tent filter is still clogged after this step, you will need to dig deeper into the carbon particles because the problem will most probably be there. Lucky for you, I have written an article on grow tent’s carbon filter lifespan and how you could clean and reactivate it so that you can maximize its efficiency like a brand-new one.


The carbon filter is one of the most critical pieces of equipment in any grow room. A clogged filter is one of the most common issues that a grower faces. Running humidifiers alongside carbon filter is the most common mistake any newbie grower make and it is important to know how to fix it if it happens to you. Thankfully, there are a few tips and tricks that you can use to avoid a carbon filter clog in the first place.

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