Prompt Title: Grow Box Exhaust Recommendations.

To calculate the appropriate exhaust fan size, you need to know the desired air exchange rate for your grow box. In general, it's recommended to replace the air inside your grow box at least once every 3 minutes. Some growers prefer even faster air exchange rates, such as once per minute, depending on factors like plant density, temperature, and humidity.

First, let's convert your grow box volume to cubic feet: 1.46 cubic meters * 35.3147 = 51.56 cubic feet

Next, we'll calculate the required CFM (cubic feet per minute) based on a 3-minute air exchange rate: 51.56 cubic feet / 3 minutes = 17.19 CFM

Now, let's find out the CFM of your current exhaust fan. Although you didn't provide the motor specifications, we can estimate the airflow capacity based on the duct diameter. For a 100mm (4-inch) duct, a typical exhaust fan would provide about 100 CFM. It seems that your current exhaust fan is more than enough to handle the required air exchange rate for your grow box.

However, if you're still experiencing issues with odor control, there are a few things you can try:

1. Ensure that your charcoal filter is clean and functioning properly. Replace it if necessary.
2. Improve the sealing of your grow box to prevent odors from escaping.
3. Consider adding a second charcoal filter to your current exhaust system. This may be more effective than adding another exhaust fan, especially if your current fan is already providing enough air exchange.

Remember, it's always a good idea to consult with the manufacturer's specifications for your exhaust fan and filter system to ensure optimal performance.

Thank you for providing the additional information. Let's convert the provided specifications into values we can use for our calculations.

Motor power: 13W Maximum airflow (vazão máxima): 95 cubic meters/hour

Now, let's convert the airflow rate to CFM (cubic feet per minute): 95 cubic meters/hour * 35.3147 (conversion factor) / 60 (minutes per hour) = ~56 CFM

So, your current exhaust fan has an airflow capacity of about 56 CFM. Based on the previously calculated required air exchange rate of 17.19 CFM for a 3-minute cycle, your exhaust fan should be adequate for your grow box.

However, as previously mentioned, if you're still experiencing issues with odor control, you may want to:

1. Ensure that your charcoal filter is clean and functioning properly. Replace it if necessary.
2. Improve the sealing of your grow box to prevent odors from escaping.
3. Consider adding a second charcoal filter to your current exhaust system.

Keep in mind that adding another exhaust fan may not significantly improve odor control if the problem is related to the effectiveness of your charcoal filter or the sealing of your grow box.