New light brought new heat!!

I got my CFM (cubic feet per minute) formula from AC Infinity. If I remember correctly it was tent's LxWxH = CFM. For additional items add percentages: +20% for ducting, + 20% for each duct elbow, 60% for carbon filter, 20% for muffler, 50% for LED lights. Add those percentages and multiply that total times the volume of the tent. That should get you in the ballpark for a complete air exchange every minute. I'm not actually measuring the air movement but rather calculating the amount of air flow needed for the situation in order to size the ventilation accordingly. I like 6" ducts. After awhile you just sort of know what you need by the tent's actions. A slight negative pressure should suck the tent walls inward slightly. I hope this makes sense; it does in my head at the moment, but I'm really baked on some dry-sift kief hash as I write this. I'm no expert by any stretch of the imagination. Others have way more experience than me.

Cynister said:

50% for LED lights.

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Why would their be a percentage change of 50% for leds?!? Unless your running some skinny air cooled hps tube with a chubby bulb but any cheap chinese hood is only gonna lose a slight amount of air flow.. probably cause it’s leaking lol

There's always some heat to take into account with LEDs, although it is very low compared to some other choices. I don't want the minimum CFM to be your max capability. This allows good ventilation with adjustability to increase or decrease as the need arises. Understand, this is a passive intake air set-up drawing from an adjacent room and exhausting outside. The ability to dial-up or dial-down the airflow allows a range of flexibility to handle the humidity changes with reasonably low cost and less equipment. I like to keep it simple.

My tent has finally been stable. However the lights are only at 75% right now. I have not tested stability at 100% yet.
Here are the current environmental controls.

• 2 AC Infinity 6 Inch Fans With Carbon Filters. Set to exhaust outside at 89F & 70% Humidity (Sensor is as center in the tent as possible with a foil shield)
• I have small fans blowing directly on 3 of the 4 lights
• Active intake set to a temp trigger above 90F, with the sensor hanging right next to the driver of the light with no fan. (Basically this only turns on if the exhaust cant cool the tent alone)
• A humidifier that is always running right now, i have a humidity triggered outlet on the way that i will set be set 5-10 points below the where the exhausts are set to dump.

The tent is pretty stable with the temps in the low 80s and humidity has been mid 60s. VPD right around the 1.0 mark.
A few days of this stability was very noticeable in the plants and they are doing much better. Mind you they were fresh clone transplants 2 weeks ago and were topped 1 week ago. All signs of stress are gone and vigor has returned.

Kinda expecting a pretty big boom in growth which is going to change everything up im sure. It'll be interesting when there actually a full canopy in here.