[its.always.420]

Hey all, long time lurker here. Legal medical in USA. Took a break from growing for a few years due to living situations, now getting set up bigger and better in my unfinished/unconditioned basement. Ambient temps 55-75 year round. Stays near 65 most of the time.

Here's the setup:

5x5x6.5 tent/1000w hps cooltube & e-ballast for flower.
2x2x5 tent/400w MH vented hood & e-ballast for veg.
random cabinet/110w PL-L for clones and seeds.

Here's the issue: COOLING. Since I was a closet grower for a long time, I've got a 4" Can S series and a hydrofarm 4" squirrel cage. I've picked up a Can Max Pro 6" (420 cfm) and a can66 filter. Trying to find the best way to utilize it and starting to bang my head against the wall. I'm worried about what I'll do when it's 90 degrees outside this summer, and my basement is over 70. BTW, temps are measured in areas shaded from radiant heat, but below the intended canopy.

The MaxPro is waaay too much to vent the 5x5 with alone. Temps actually sit 5 degrees higher with the fan on Hi (78-82). I don't think there's enough time for the air to mix. On low I get 75-78 with ambient of 62. This seems hi to me, i ran 300w of HPS in the 2x2 with only a 10 degree gain. Again, I don't think there's enough time for the air to mix before leaving the tent. And yes, I have 2 fans inside tent, 1 is oscilating and both are hung from top of tent and blowing around/under the hood.

I am currently venting the 1000w cooltube and the 400w MH in series (400->1000->fan->) with the 4" can and reducing it to 3" to go out an unused chimney flue with a 3" liner. This all seems to work fine and temps didn't change when I added the 400 on the end of the run. IN fact the veg tent is sitting at 73 with no plants in it and I'm pleased as punch :-)

The MaxPro is venting the 5x5 tent on low setting, and it's still sucking the sides in with both tent vents open. I get the same temps with this setup, that I did with the 4" can taking air directly from the tent through the light. Not disappointed with m purchase, just don't think I'm using it correctly.

I don't want to run the filter>light>fan thing because that's a lot of fan to be running when lights are off. It's nice to keep some negative pressure at dark time but there's no reason for 4x air exchanges per minute and it dries the plants out faster than necessary.


Anyone got any creative ideas for my setup? Looking for optimum temperature control and efficiency. Can the 6" maxpro compress air down to go through the 3" chimney liner?? Seems bigger fan for light and smaller fan for carbon would work better. But then will the can66 filter work with a 4" fan?? I could use the squirrel cage for a intake fan...but 95 cfm seems futile...

He're the equipment list again:

1000w HPS cooltube
400w MH vented hood
6" 420 CFM mixed flow
4" 125cfm inline
4" 95 cfm squirrel cage
(also a few bathroom fans 50cfm and a pile of PC case fans xD)



Let's hear your brainstorms!


edit: holy fuk I didn't realize my post was that long. Thanks for reading!!

[Phaeton]

The bud room runs one CFM per watt. That means two 2500 CFM intake fans for the 5600 watt room.
The room temperature remains within six degrees of ambient, 83 degrees with a 77 degree lung room. The house runs warm in the summer with temps reaching 80 in the living area.
Using the same CFM as extraction did not mix the air in the room, it just sucked air from around the outlet, even with the intake set up kittycorner to the outlet.

Intake is high and low (two fans) along a wall so the air forms a swirling vortex in the room, thoroughly mixing the air before exhausting.

Many ways to skin the cat, this is mine. The object is to stir the air around the plants, whatever it takes to do so. A separate stirring fan was used for years.

[its.always.420]

Thanks for your input Phaeton. Are you suggesting I add an intake fan?

I have also tried measuring my exhaust air from the room...remember HPS is cooltubed on separate duct and fan...and it's 71 degrees, 5 degrees above ambient. Mabye I'm measuring radiant heat in the tent...but I've done all i can to get my temp sensor insulated and in the shade. Guess we'll just see how things shake out in 2 weeks when the girls are scheduled to make their appearance.

[its.always.420]

So I was still stuck on the radiant heating thing and decided to try....a piece of tent repair fabric, mylar side out, over thermo sensors. Boom, 70-72 degrees. Blew some vape in vents to see where air flow was going (love the clear window!) adjusted circulation fans and Bob's your auntie.

Now on to build my watering sissie....

[Snook]

Originally Posted by Phaeton

The bud room runs one CFM per watt. That means two 2500 CFM intake fans for the 5600 watt room.
The room temperature remains within six degrees of ambient, 83 degrees with a 77 degree lung room. The house runs warm in the summer with temps reaching 80 in the living area.
Using the same CFM as extraction did not mix the air in the room, it just sucked air from around the outlet, even with the intake set up kittycorner to the outlet.

Intake is high and low (two fans) along a wall so the air forms a swirling vortex in the room, thoroughly mixing the air before exhausting.

Many ways to skin the cat, this is mine. The object is to stir the air around the plants, whatever it takes to do so. A separate stirring fan was used for years.

I agree P. but I've been using one of these at the base of each plant pointing upwards for low to high mixing of air since they were under $5 each https://www.amazon.com/Holmes-Mini-V...s=personal+fan they cost more now (3X-4X more) but they are still inexpensive and they last a very long time.