Is my hood to blame??

[OZZ_]

So heres the situation.

Im having some temp problems that I cant explain. If anyone could give me some insight that would be kicka$$.

I have a DR120 48"x48"x78", a 600w HPS digi, an easycool 6 aircooled hood from HTG, and a 424cfm growbright fan.

Ambient temps in the room are 78-80 deg. I currently have my plants about 18" from the hood. Temps are about 92 degs in there with the 424cfm fan running full blast! Im only growing bhut peppers at the moment but either way Ill need to rectifiy this with my equipment before I do a MJ grow.

I double check temps as you can see here with my laser temp gun. On the leaf surface temps are much lower ... but still ambient temps INSIDE the tent at the plant level are still in the low 90's.

I have all three 5" x 14" square vents wide open with a good amount of airflow into the tent.

What gives?? Now heres the thing .... Theres so much air sucking into the open end of the hood it will literally suck the whole hood and ducting towards my hand if I get my hand within an inch or two of the opening. Still theres a ton of heat radiating through the glass down towards the plants.

How is this even possible!??

Is it my hood? Its almost as if the glass is too thin on my hood. Im tempted to go buy a new hood! Something with thicker glass. Then again ... if the glass was thicker would that subtract from the lumens reaching the plants?

The hood doesnt seem to be very well made, it is my first aircooled hood so I dont have anything to compare it too.

Heres some pics of the setup. Thanks for any input you guys could give me. I see peeps running this size tent with a 400 something cfm fan on only half speed WITH a freaking scrubber. I dont have a scrubber and I got this fan cranked to the max and still high temps. WTF??

 

[SuperSizeMe]

I would start by raising my hood some, 12"-16" at least, maybe a second circulating fan, blowing straight up at the light.

With that amount of airflow it should be cooler.Maybe try unzipping the door, at the bottom, during lights on.

GL

SSM

 

[mdk ktm]

First thing, please panda plastic that window. If you go in there at night there will be an orange glow across your neighborhood.

And I would say have a fan blowing from the bottom. That fan you have on the top is just blowing hot air down.. unless you have it pointed to the opening in the hood. Do you have central air at your house?

You could insulate your ducting, and put the inline fan outside the tent too.. That would drop it a couple degrees. Also one of those insulating things for the hood. I Use them and i love them.

 

[milehimedi]

it looks like your ducting has quite a few bends in it. your effective cfm is significantly less with all those turns the air has to take.

 

[odium33]

it looks like your ducting has quite a few bends in it. your effective cfm is significantly less with all those turns the air has to take.

yes that is what i was about to note. try to get it totally straight through there... your fan may burn out from the heat faster, but you lamp will be cool.... and is that really what you are growing in there?

 

[Graham Purwatt]

i'd duct the light
intake to outside the tent and get some of those bends out.insulated ducting does help too. i have 2 600's in
a 5'x5'x7h homemade poly tent with a scrubber and the same 424 cfm fan to cool them both and my temps stay around 82f,90 on the hottest day in central fla.

 

[Graham Purwatt]

and both my hoods are the easy 6's also

 

[OZZ_]

Thanks for the input guys, really appreciate it.

To answer your questions:

1) The hood is already 18" away from the plant tops as it is, 20" away from that thermometer.... no way I should be that hot in there. I mean ... 14 deg above ambient!??

2) I do have central air. The glowing window syndrome really isnt an issue as of now. I have it running 12/12 from 7 to 7 so the sun is up when the lights turn on and the sun goes down just before they shut off. Even in the middle of winter it will only be an hour or so before lights out so no worries there. Plus, yes ... its just hot peppers lol (for now).



- So Ill definately put that little fan down at the bottom somehow and get it blowing towards the light itself, first thing. As far as the ducting goes - insulated ducting sounds like a good idea. The bends though.... How am I suppossed to get the bends out when both the window Im exhausting out of and the hood itself needs to be lower then my exhaust ports on the tent. As the plants grow Ill raise the light obviously and that will slowly straighten it out, but for now Im already 18" away from the plant tops so raising the hood anymore (in an effort to straighten the ducting out) really doesnt make sense .... I just gotta think theres a better way. Plus, I dont see others with this same equipment having problems. I mean.. Im 10-14 deg over ambient here.

I do know you guys are completely right about the bends and the reduction in CFM. The thing is ... even with those bends and the way I have it rigged up .. there is so much air suction that it will literally pull the entire hood and ducting towards my hand if I put it within and inch or two of the opening on that hood. Thats a lot of cfm going through that opening. I cant see MORE CFM being needed (although I realize straightening the ducting out would give me more).

Is it possible I have to MUCH CFM?? Maybe the cool air is just coming straight in through the intakes and out the hood without really circulating around the plants first??

Graham - I thought about connecting ducting to the intake, then getting a smaller exhaust fan for the tent itself... if I cant figure out what the hell is going on Ill rig it up that way and see if theres an improvement. It really just seems like way to much heat is radiating THROUGH the glass itself. Like its too thin. I guess though if you have the easy 6's and having no issues it must not be the hood itself??

 

[Graham Purwatt]

you don't need more cfm,you have plenty.i would exhaust into the room and maybe crack the window so air can come in instead of out,reducing the bends will help some but you don't have to worry too much.also once you have a full canopy in there it should drop a degree or two.like i said,i have a scrubber up in the corner of my tent and it stays a decent temp with 2 easy cool 6's at 600 watts each and 1 424 cfm fan.my exhaust does blow into another room but it is a hot room with poor insulation and is usually cooler in my tent

 

[OZZ_]

you don't need more cfm,you have plenty.i would exhaust into the room and maybe crack the window so air can come in instead of out,reducing the bends will help some but you don't have to worry too much.also once you have a full canopy in there it should drop a degree or two.like i said,i have a scrubber up in the corner of my tent and it stays a decent temp with 2 easy cool 6's at 600 watts each and 1 424 cfm fan.my exhaust does blow into another room but it is a hot room with poor insulation and is usually cooler in my tent

Well, I initially had it exhausting into the room. That did NOT work. It brought the rooms ambient temp as well as the ambient temp in the tent to 99 deg!! lol.

No joke. It literally turned my spare bedroom into a sauna. Ya so riddle me that one. Right now Im exhausting OUT the window and its 78 deg ambient in the room, 92 deg ambient in the tent at the soil surface. When I exhausted into the room, the rooms ambient temp went to 99 deg and the temp at the soil level was 99 deg. LMAO ... doesnt make sense at all. Either that or Im dumb as a rock cuz I cant figure it out

Why the hell was the tent zero degrees above ambient when I vented into the room (because it was 99 deg in the room and 99 deg in the tent) but now that Im venting out the window Im 12-14 degrees above ambient (78 ambient 92 soil surface). WTF ... lol??

 

[Graham Purwatt]

wierd but it bears toying with.i shit you not,i have about the same measurements on my tent,2 600's in easy cool 6's and 1 424 cfm fan and i'm in the middle of fla.insulated ducting on the exhaust end of the light to the fan will rid you of some of the heat,you'll have to have a scrubber for smell too so i'd go ahead and throw that in.i have 1 circulating fan at light level to blow around the air in mine but i have 3-6" ducts for intake and my temps are consistent.maybe duct your central h&a duct to the tent intake? i can't imagine why its staying so hot.my hoods have the standard stuff they come with,no thicker glass or anything.it may make a diff if you make sure that the socket end of the hood is the exhaust end so you are wide open on the intake,it seemed to help with mine but i may have just been high at the time.i keep the door to that room cracked and the window in the next room open so air can flow good,hope some of that helps bro,i wish you luck

 

[OZZ_]

Thanks for the help bro.

What size circulating fan do you have blowing under the lights? How do you have it mounted??


You know... I dont have the socket end as the exhaust end as of now ... and I probably should so Ill make sure to switch that around asap. Also, Ill get some insulated ducting for the stretch inside the tent. A circulating fan underneath would help a ton I bet too. I actually have more surface area for intake then you do so I should be more the adequately covered there. I have all three 5"x14" vents open.

I appreciate the input Ill have to give it a shot. Hopefully it will work.

 

[Graham Purwatt]

i just use a standard 12" circulating fan from wal mart.i mounted it upside down in a ghetto fashion with zip ties screws and a shelf bracket so that it hits between the top of the canopy and the bottom of the hoods,not sure how that would work in a prefab tent but i'm sure it could be done.the ins.ducting will quiet you down alot too,nice added bonus.all the little things that drop you down a degree or two add up.i had heat issues myself when i first set up but worked them out eventually with help from these guys.one cat said he was cooling like 4 1000's with around 500 cfm,if that can be done then 424 on a 6 should be easy.if none of that does it you could try hooking an intake to the hood from outside the tent but then you'll need another fan for scrubbing and exhausting the tent.i started out that way with the 424 and a smaller 4" 170 cfm fan and the way i have it now is better and more effecient

 

[OZZ_]

All your suggestions and experiences are right along the lines of things Ive been considering.

You know.... on advice from another board... I tried putting the thermometer underneath one of the leaves... in the shade rather then in direct light. Guess what .. lol .... 80 degs. Exactly ambient temp. So I wonder if its just heating up the plastic on that thermometer. Also, of course the laser temp gun is going to read out the same since it reads surface temps not ambient air temps anyway.

So Im thinking my ambient air temps are probably spot on this whole time. It would make more sense anyway. Im thinking I should get a different thermometer. Maybe one with a probe or something. That way I could hang it in the canopy somehow and not have to worry about the entire thermometer casing getting heated up.

Good advice here though I appreciate it all. Now I wonder how far I can turn down that fan and keep it at ambient

lol

BTW to switch to insulated ducting do I just go buy insulated ducting as a whole product or do I go buy insulation for the ducting I already have? Im not sure if its just ducting that comes insulated I need to go buy or some sort of wrap that goes around existing ductwork.

 

[SuperSizeMe]

Good stuff right here...

At Casa De Pot

 

[HydroJen]

First thing is to convince yourself that there is nothing wrong with your hood. High discharge lights give off a lot of heat. Glass conducts heat, otherwise you wouldn't need oven mits with glass pans. You will never suck out all the heat.

At least duct the intake so that cool outside room air is being pulled the the hood, instead of the hot tent air.

Next, when u can afford it, buy a small airconditioner and vent the cold blow into the tent.

 

[dunkydunk]

Getting accurate temps is crucial. If your tent was 12-14 degrees above ambient, you'd feel that heat when you opened the door, or even seeping out of the zippers. Do you?

I've had bad readings from simple thermos. Direct light will throw them off, so will holding them in your hand. I once had a t5 raise the temp on the dark coco to 85 on my seedlings, but the circulation was so good in my tent that the air temp was 75.

Digital and analog thermometers will often give me different readings by a few degrees, I'm never quite sure which one to believe.

As for insulated ducting, you can buy it together or in separate pieces. If you buy it together it saves you from having to reach your arm into the itchy, nasty insulated tube to pull the ducting through. I hate insulation. The traditional stuff at the Home De Pot works well but it's bulky, especially in a tent. I saw some thin walled insulated ducting available at worm's way, but I don't know how well it works.

As for your fan, get it to blow across the canopy, not knock the hot air down from the ceiling. You can even extend a little more ducting up off the intake of your hood to pull that hot air out. Intake where it's cool, exhaust where it's hot.

 

[mdk ktm]

I just buy the 6" duct sleeves, they have fiberglass insulation wrapped in mylar type shit, they come in like 6 foot lengths.

 

[SuperSizeMe]

I just buy the 6" duct sleeves, they have fiberglass insulation wrapped in mylar type shit, they come in like 6 foot lengths.

I was actually thinking of using some of my leftover Reflectix for in-between my lights.I'm using the rigid aluminum (no-bends) and it wouldn't apply to this situation.

Cut for length/diameter and velcro to attach, for removal if needed.

Just throwin' it out there

/back on topic

 

[OZZ_]

Thanks a ton for the good tips everybody. This thread is kind of a my bad though, my temps have been fine the entire time. The thermometer casing was getting heated up by being in the direct light. Once placed underneath a leaf (with good airflow all around it) it dropped to 81 deg's in a matter of minutes. Also, leaf temps checked with my laser gun are 80-83 degs. Soil temps checked with the laser gun are 74 deg.

I guess it was just a matter of that plastic casing getting heated up by the light (IR?? *shrugs*).

Ive learned a sh*t ton from this thread though and it will come in handy when I upgrade to two 600's and a bigger space.

I appreciate it! Heres another little gizmo I like having around:

Horse hair hygrometer. Suppossed to be the most accurate around and Ha'are brand is top notch. For 50 bones it better be lol. I bought it when I was growing fungus but no reason to have a $50 hygrometer sitting in storage.