Room vs Tray temps

[LSWM]

Hello everyone,

I am a long time stalker of these forums, first time poster. Been running vert donuts since my second run ever, going on my 5th harvest right now.

Method: DTW Drip Coco in 2 gal pots. 5-6 plants per light, some 1ks, some 600s. Maxibloom + Koolbloom powder. I have always ran bare bulb, and just controlled room temps, however this time I built an octagon of trellising around me trays and attached orca film to the outside. This issue is the disparity in temps from just outside the tray to the inside. I have a fan blowing up from the bottom of the tray over the bulb, as well as ducting immediately over the top extracting hot air. Temps are steady 75-80 outside tge tray, in the main flower room, and 85-90 inside.

Question: Is this too hot? Should I be worried about baking the plants @ 90 inside the trays? i never have had this problem until adding tge orca gilm for extra reflection, and it seems weird to me because the main flower room is still within acceptable temps.

Would really love to hear from some of the extremely knowledgeable people here in this forum. Much of what I've learned already has come from DHF, HGO, Lazyman, and many others. Would love to get an answer from one of the veterans.

Thanks in advance!

 

[SirStynkalot]

Yeah, that's really hot. Really really hot. Highest I've ever heard someone claim they pulled off well in tightly controlled circumstances was 86. Most say 82-83's the max with CO2. I do my best to keep 78 degree hotspots.

If you want to leave the orca up you may want to figure out how you can move more air across the barrier. If you have any extra inline fans or something that'd be ideal. Pump more in low and let what you already have set up move it around in there. If not even a couple honeywell fans or something would go a long way.

 

[LSWM]

Yeah no co2 here, as its getting to summertime, and there's no way I'm getting around ventilating outside.

I'm not sure of anything else I could do to drop temps.

I've already got way more ventilation than necessary, with 1 fan/scrubber venting directly out of the flower room. Pulling cold air from somewhere else would be ideal, but the logistics of doing so aren't easy to handle. I'm already venting out under the house, aside from opening a window or cutting a hole I'm pretty stuck with the current ventilation. Both of these solutions would create more issues with noise and security.

I could dim the lights down to 600, if necessary, or possibly setup a small window ac i have laying around, but again the issue of ventilating the hot air produced by the ac, I can't exactly put it in a window and run that bitch all night.

Guess I could tear down the orca film, but that'd really be annoying as I spent countless hours designing/building these trays, and I must say they look fucking beautiful. The amount of light reflected is amazing. The room is much darker, and its so obvious much less light is being lost.

If everyone agrees that temps are unacceptable I guess I will start by dimming my lights, or just throwing some 600s in for now, and attempt to get the ac going and vented. Ah, the joys of constant dialing with new setups, that are constantly getting bigger and bringing brand new unexpected challenges.

 

[LSWM]

I was discussing the issue with another grower buddy, and he suggested using a cheap 6 in duct booster asan intake for each tray . While I'd prefer to avoid the extra electrical/wiring, his idea may just work. I was also toying with the idea of just cutting an inch or two off the bottom of the orca film, just to allow more cool air into the tray.

Hopefully one of these ideas work.

 

[SirStynkalot]

That's exactly what I was saying, but use inline fans or even a honeywell or box fan rather than a duct booster. I don't think the OP was getting that.

Duct boosters are designed to push along already moving air. They're not designed to push air that's at a standstill. If you try to use one that way it'll probably burn out within two months - 6 weeks if you put any actual ducting on it. Beware of duct boosters - every grower tries them once because they're so cheap then realizes shortly after that they just pissed their money away.

 

[Bennyweed1]

Sounds like you just do not have enough air movement. What CFM is your exhaust? Do you have intake or is it passive?

You either need a intake fan and larger exhaust

Or you thermometer is being heated by infrared heat off the bare bulbs, try moving its location.

 

[LSWM]

Okay, so I was outta the house for ~24 hours, and came back to snow on the ground. High temps were definitely not a problem while I was gone, nor last night.

It seems that the 90 degree reading I've been getting was influenced, as Bennyweed said above, but the infrared heat. Here is a picture of two thermometers next to one another.

As you can see the one behind the pot is reading 75, while the one in the direct light is reading ~90F.

At this point, I'm starting to think that things are fine with the current setup, but I will continue to keep a close eye on temps.

 

[LSWM]

The room in question is 12x20, but has vaulted ceilings with ~2' of height at the edge, and 8' directly in the middle. There are 3 - 4x4 trays each with it's own ventilation directly above. An 8 inch CanFan HO covering 2 trays, and another 6 inch CanFan HO covering the last, with a Carbon Filter which exhausts out of the whole house. Total CFM moving out of the flower tent is ~1.2k. Total CFM being exhausted from the house is ~350 after scrubbing.

Here are some pics of the whole room so you guys can get a better idea of what I have setup.

 

[LSWM]

Flower Room Pics (continued)

 

[LSWM]

In the same building, downstairs, I've got another room flowering under a 600 in a hood. (Sorry about the shitty HPS pics)

 

[LSWM]

And finally just for kicks and giggs, here is my veg room.

 

[LSWM]

Sounds like you just do not have enough air movement. What CFM is your exhaust? Do you have intake or is it passive?

You either need a intake fan and larger exhaust

Or you thermometer is being heated by infrared heat off the bare bulbs, try moving its location.

My intake is passive. Here is the answer to the CFM question from a few posts above. You can check out the ventilation setup in the pics above.

The room in question is 12x20, but has vaulted ceilings with ~2' of height at the edge, and 8' directly in the middle. There are 3 - 4x4 trays each with it's own ventilation directly above. An 8 inch CanFan HO covering 2 trays, and another 6 inch CanFan HO covering the last, with a Carbon Filter which exhausts out of the whole house. Total CFM moving out of the flower tent is ~1.2k. Total CFM being exhausted from the house is ~350 after scrubbing.

 

[LSWM]

That's exactly what I was saying, but use inline fans or even a honeywell or box fan rather than a duct booster. I don't think the OP was getting that.

Duct boosters are designed to push along already moving air. They're not designed to push air that's at a standstill. If you try to use one that way it'll probably burn out within two months - 6 weeks if you put any actual ducting on it. Beware of duct boosters - every grower tries them once because they're so cheap then realizes shortly after that they just pissed their money away.

Thanks for the tip, I am the OP btw, lol. I have used a duct booster to exhaust a tent in the past, and the thing burned out on me, but I also was trying to use a speed controller on it as well, like a dumb ass. The controller says clearly not to use on brushed motors, so I went ahead and did it anyways. I figured that was the reason it burnt out, and not from being used to pull still air.

 

[SirStynkalot]

Sry LSWM I was a bit stoned when I wrote that. Usually am when I'm on here, strangely enough.

Yeah, it's not just the controller. Those are meant to assist with long stretches of ducting - if you had, say, 40' of 6" line running all over your room you might want a duct booster or two to help push it around the curves. That's what they're designed for.

I didn't think to ask if you had your thermometer in the light or not >.< yeah you can't do that and get any accuracy.

You should have enough power for exhausting that room - maybe 400 "real" cfms for about a 1600 cf area (bends, ducting, and filter all reduce airflow). Exchange once every 4 minutes. If you can keep temps down at that you're good. "Minimum" exchange you want for CO2 purposes is once every 5 minutes. Of course, that's assuming you have a very large passive intake hole. If not the fans are sucking against a closed box. Intake fans for rooms that size are usually a very good idea if you can work it.

It doesn't look like you have much in the way of air movement inside the cylinders. Exhaust high, honeywell low, plants well back from the moving column. Was I missing something? If not, you may want to think about some way to stir up the air in there. Remember, having CO2 in the room doesn't do any good if you can't get it to your plants. Putting the Orca up like that may have helped greatly with light efficiency but it probably also created some dead spots inside the chambers that weren't there before.

 

[LSWM]

Sry LSWM I was a bit stoned when I wrote that. Usually am when I'm on here, strangely enough.

As am I. Haha

It doesn't look like you have much in the way of air movement inside the cylinders. Exhaust high, honeywell low, plants well back from the moving column. Was I missing something? If not, you may want to think about some way to stir up the air in there. Remember, having CO2 in the room doesn't do any good if you can't get it to your plants. Putting the Orca up like that may have helped greatly with light efficiency but it probably also created some dead spots inside the chambers that weren't there before.

Pretty spot on. So do you think cutting somewhere from like 3-6 inches off the bottom of the orca and adding an oscillating fan at that level would be enough to increase air exchange? Or even just a simply clip fan? Got plenty of those.

I have a super old CO2 monitor and Controller from a buddy. (Like 15 years old) Brand is ControlWizard. I do not currently have any CO2 production equipment (I have a natural gas wall heater in my "lung room" but it is ducted out of the house, and I doubt it produces much CO2 inside), but I have ensured that the monitor is accurate and calibrated vs other growers monitors, so I will pull that thing out and try to get some readings around the room. If there are any dead spots, that things should let me know with enough data I think.

You should have enough power for exhausting that room - maybe 400 "real" cfms for about a 1600 cf area (bends, ducting, and filter all reduce airflow). Exchange once every 4 minutes. If you can keep temps down at that you're good. "Minimum" exchange you want for CO2 purposes is once every 5 minutes. Of course, that's assuming you have a very large passive intake hole. If not the fans are sucking against a closed box. Intake fans for rooms that size are usually a very good idea if you can work it.

The main flower room is ~950 cu ft. The downstairs flower is another 288, and the Veg is ~200. There is also a sort of "lung room" which is another ~1000-1500 cu feet. Every "tent/room" is being ducted, with their own inline fan, into the lung room, with my carbon filter and a 6 in 440cfm inline fan ducting directly from the main flower, out of the house.

Unfortunately there is only passive intake, which I assume mainly comes through the eaves of the house, and through the cracks around the door in the lung room.

Any recommendation on total outside exhaust CFM to maintain good CO2 levels in the house? I have toyed around with the idea of putting the fans on timers and running them only during lights on, in order to maximize outside air circulation to tents with lights on, but haven't gotten around to it.

I also have an Indoor Climate Controller from Control Wizard, but not quite sure how it could help in this High Heat/Low Humidity Situation. The fan would be on anytime the heat was his, thus bringing in cool/dry outside air. Doesn't seem like there's anyway to add any humidity unless the room cools off.

 

[Bennyweed1]

The thing I have about duct booster is if your running a high CFM fan.. say 900+ and have a 125cfm inline duct booster, I think it would actually cause restriction.

I could be entirely wrong in that assumption though.

And the thing about the thermometer. If you take any thermometer and place it in direct sunlight, even on a cooler day, low 60s, it will still read 90-100f.

Now the question is, if your thermometer is being heated to 90 degrees via infrared heat, then theoretically, the plants, or parts of the plant, are too. Whether or not that is a good or bad thing, Ill leave that up too the thermo dynamics physics experts.

 

[Bennyweed1]

And when you say 1.2k out of the flower tent, are you saying you have a 1200cfm fan exhausting out of the tent into the attic, and then a 350cfm exhausting the attic?

 

[LSWM]

And when you say 1.2k out of the flower tent, are you saying you have a 1200cfm fan exhausting out of the tent into the attic, and then a 350cfm exhausting the attic?

There is no attic, hence the vaulted ceilings. 1200 cfm exhausting the flower room. This is done with two fans, one 850 cfm 8 inch exhausting into my "lung room" and another 440 cfm fan exhausting from the flower room into the crawlspace beneath the house.

 

[SirStynkalot]

Huh.

well, if you already have clip fans you may as well try them before you start cutting your new walls up. Couldn't hurt. Ideally you're looking for a light breeze or at least some sort of air circulation around every plant.

As far as the lines go, they sound kinda screwy. The air has to come from somewhere and go somewhere, and if it's a small hole it needs a fan on it. You have a lot of CFMs but it sounds like it's pulling from and pushing to dead space. Sounds like you may want to research ventilation setups (there's a sticky on a subforum somewhere around here) or just add CO2. If you want to double check before you do any major changes it might be worth getting a new CO2 tester... I believe they make one use pads that might work for a one time spot check.

When calculating fan rates you have to factor in duct length, diameter, and type (flex duct creates a lot of drag), number and angle of bends in flexing, and filter drag (which reduces airflow by I believe about 75% by itself). Going by that I'd be surprised if an 8" outtake and a 6" intake pulling from and pushing to more open space would be enough for your room. Off the top of my head I'd guess you'd want at least an 8" intake and 10" outtake. Could be wrong though - you'll have to do the math out to double check that.