Adding a booster fan to improve outgoing air flow?

[Rik]

Hey guys. I have a tent with an 8” duct system. I have a TerraBloom carbon filter and 710 CFM duct fan inside the tent, and a Phat inline carbon filter later on down the line for improved air filtration.

I have quite a lot of duct work with lots of turns, and at the very end where the air is finally exhausted, the flow is pretty weak. I want to improve my air flow and was thinking of adding a TerraBloom 8” booster fan:

https://terra-bloom.com/collections/booster-duct-fans/products/8-duct-booster-fan-terrabloom-dbf8-400-cfm

But, in a similar product description made by AC Infinity, it says that it’s “Please note this booster fan cannot be used standalone in high static pressure applications like room ventilation. Additionally, it is not suitable for use in applications with restricted airflow like systems that use carbon filters.” See here:

https://www.acinfinity.com/hydroponics-growers/booster-duct-fans/raxial-s8-inline-booster-duct-fan-with-speed-controller-8-inch/?gclid=CjwKCAjw3riIBhAwEiwAzD3TifHM7pbUChYCOqV0XHE0tunlgwHTSAXzCXVF_grdqrAb1Q5NdGa3wRoCaykQAvD_BwE

Can I add this TerraBloom booster fan in my ducting to improve air flow? What’s with this warning on the AC Infinity product??

[Rik]

I had a feeling that this thread would go unanswered. No big deal. As an engineer, I’ve always been more interested in the technical and gear driven side of stuff.

For the benefit of the forum, and for increased growing knowledge, immortalized forever online, here is the response from TerraBloom on this subject in case someone has the same question in the future:

”It is not about safety, but rather about the end result you’ll get. If you are planning to connect a cheap $30 fan into system with a lot of static pressure then the added airflow you will get will be quite small, around 100 cfm or so, because that fan will be hampered by all of the restrictions created with the filter, long duct and the duct fan you have on the same line. These cheap “booster” fans are not effective in applications with auxiliary equipment causing restrictions, or in other words they do not handle static pressure well and loose a lot of airflow with each incremental increase in pressure/restriction.”

✌🏻

[TOKABIGONE]

Hey Rik, sorry, I was reading this late and started to look at air flow through ducting and turns then fell asleep, lol! I did fin info that talked about it say any more than a few feet or a turn cuts air flow rapidly. Unfortunately I can't find it again this morning. In your case and with the added restriction of another filter I will say you definitely need a booster fan. I think I would put it right before the filter IMO.

[Rik]

Thanks TOKABIGONE! Yeah I’m gonna give it a try. It might not do much, but it’s worth a shot because I need to increase the airflow one way or another. I’ll probably post back here after it’s installed to share how it went to round out the topic in case anyone finds this useful in the future.

[Rik]

As promised, in the interest of adding to our collective knowledge for anyone who has this question in the future…

I received and installed this booster fan in the middle of my ducting last night, and there is a small difference in the net breeze exhausting out at the tail end. It’s not big, but every little hit helps. Here’s the final response from TerraBloom customer service when I asked him to verify it was safe to install it in the manner described, and whether or not it made a difference where I put it:

“It is safe, the location will not matter much. Install in a place where the noise from the fan will be the quietest.”

It’s actually not loud at all. Hope this might be of use to someone some time out there.

[UndergroundFarmer]

I added one in my 4x4 flowering tent to assist the 4" AC Infinity doing the heavier lifting. It was just an inline booster fan from Home Despot rigged with adapter pieces. It helps, but I may have to consider upgrading to another 4" or replacing it with a 6" or 8" fan.