Need a little help figuring out what setting I should have my exhaust fan on

[the123321]

I have a 32x32 tent that is like 5.5 feet tall which I figure to be around 40 cubic feet. I have the 240w kingbrite quantum board led with the ac infinity 6" fan with filter. The fan has 8 speed settings on it and I run it on setting 1 and it pulls in the sides of the tent a little and keeps the tent around 77f and 60% rh on there. It looks like the first setting is like 44 cfm and setting 2 is like 88 cfm and setting 3 is like 132 cfm on up to the setting 8 on there. I am now thinking I may need to turn the fan up some to make sure it is moving the air in the tent enough to try to prevent mold in the tent on there. I would rather not turn the fan higher than the setting 2 or 3 if that is enough cfm though I definitely do not want mold in the tent on there.

I have read on different websites that say different things about how many times per minute you want to replace the air in the tent with your fan with from 1-3 times per minute or 1 time every 2 minutes on there. How many times per minute do you recommend? How much does the carbon filter reduce the cfm of the fan? Is it like half? I have the filter then a 90 degree turn with a few inches of duct to the fan then a 90 degree turn with a few inches of duct up out the top of the tent. How much do you think that reduces the cfm the fan is doing on the setting it is on?

 

[BII]

This is an exhaust (and input pulling) fan, not to be used for "moving the air in the tent." For that, you should add 1 or more internal fans, ideally 1 of them an oscillating fan.

What matters is whether air is noticeably exchanged, such as evidenced by cooling the tent, not any specific setting. With a relatively small tent, I would think as long as you can feel warm air being exhausted every few minutes and your temperature is steady, that's all you really need.

But why not actually control the temperature, which is way more important than moving lots of air in and out of the tent and can't really be controlled by setting constant-running fan speed? Run the exhaust/filter fan off a simple cheap thermostat switch or extension (presuming you didn't get that the thermostat option with the AC Infinity fan).

 

[the123321]

Thanks. I have fans inside the tent for moving the air on the plants. I want to replace the air in the tent at least 1 time per minute with the exhaust fan. I think I have it figured out now. I am running the fan at setting 2 that is listed to be around 88 cfm which I think makes up for the filter and the 2 90 degree turn that are in the tent. I did not want the temperature control on the ac infinty fan as I use the fan to do the odor control in the tent and I did not want it to turn off if it got to a temperature or rh on there.

 

[Death The Cultivator]

Thanks. I have fans inside the tent for moving the air on the plants. I want to replace the air in the tent at least 1 time per minute with the exhaust fan. I think I have it figured out now. I am running the fan at setting 2 that is listed to be around 88 cfm which I think makes up for the filter and the 2 90 degree turn that are in the tent. I did not want the temperature control on the ac infinty fan as I use the fan to do the odor control in the tent and I did not want it to turn off if it got to a temperature or rh on there.

You only need between 3-5 air changes per minute. Why do you want it once every minute?

Your intake hole needs to be 2-3 times larger than your exhaust. Mold occurrs when there are frequent fluctuations in temperature and humidity but not at 60% RH, it could be lower if you're in flower but not by much. On top of that a 6 inch fan is excessive for 2.6x2.6 tent that doesn't even need 50cfm, opening extra vent holes will reduce pressure in the tent.

 

[the123321]

Thanks. I have read on many different websites and it looked like most of them have said that you want to do it at least 1 time per minute. If the tent is like 40 cubic feet then I figure 88 cfm when reduced by the filter on the with 2 turns in the duct would make it like at least 1 time per minute. I wanted the more powerful fan to make it to where I could run it on low instead of a smaller fan on a higher setting and I plan to use duct from a 2x2 drying tent to the 32x32 tent with the plants in it and use the fan with filter in the 32x32 to do the odor control work on it.

 

[Death The Cultivator]

Thanks. I have read on many different websites and it looked like most of them have said that you want to do it at least 1 time per minute. If the tent is like 40 cubic feet then I figure 88 cfm when reduced by the filter on the with 2 turns in the duct would make it like at least 1 time per minute. I wanted the more powerful fan to make it to where I could run it on low instead of a smaller fan on a higher setting and I plan to use duct from a 2x2 drying tent to the 32x32 tent with the plants in it and use the fan with filter in the 32x32 to do the odor control work on it.

Even a 4 inch fan will pull more than what you need - 40cuft / 1 air exchange per minute= 40cfm - add an extra 25% for each turn and filter. You just need to open extra vents to prevent too much negative pressure though.

 

[the123321]

Thanks. I have the vents open in the tent on there.