Too hot and dry in my GL80 tent

I have the GrowLab GL80 tent with a 400w mh light and 1 cheapo exhaust fan on the top and a cheapo intake fan on the bottom. One large air purifier (i use it for the fan)
2 two month old plants and a humidity box and a humidifier.

I keep the lights on for 16 hrs and its super hot I also put a fan on my room window to get the cool air in (it helps but lately its been getting warm out)
My temps and humidity at 6am (when the lights kick on) 80% at around 74F
When I get home around 6pm its already at 90F and 30% I then mist them and get the big window fan going on high. and they rest at 83F 40% until lights out.

Its my first grow and I ran into a REALLY REALLY BAD string of luck for sept. losing a lot of money to some stupid expenses. so I need to be as thrifty as possible until i recoop.
So several questions what is optimal range for temp and humidity, I thought it would be around 65 to 75f and 50-70%
I dont know if my plants need anything else besides that. They are full of leaves which makes me want to pick them off but I resist.
I heard bad reviews about COOLTUBE which is what i was thinking of getting.
What is a recommended fan out there. My room is 3.7 x 3.7 x 5.11 so cfm wise and low noise wise and important price wise. I was thinking the Can Fan.
I was going to be switching bulbs to hps to start flowering. Think I should wait until I get the temp down? I dont want to ruin the buds.
I wish I had the space to move them close to a window but I cant.
Actually I wish I had space period. I hate city living.

And of course some feed back on my setup....its pretty ghetto isnt it. lol

Thx all
I want to just stay on this forum all night but I got school and homework. There is alot of great info on here.

A guy told me once that you can leave bags of ice or bottled water in the tent. Worth a shot if you are just trying to get one grow over the line.
Bitches don't know about my thermodynamics

Im going to try that tomorrow when the lights come on...thx dude
I do need to get the grow over. I think I can budget 100 bucks right now

I have a question. Why does your light come on at 6 am and then run 16 hours shutting off at 10 pm? The coolest hours of a 24 hour period are going to be at night!! Especially during the twilight hours.

Your lights should come on at 6 PM and go off at 10 AM giving you 16 hours during the coolest part of a 24 hour time period.

That would leave the light off from 10 am to 6 pm, the hottest part of a 24 hour time period.

You have a light proof tent so I don't understand why you are running your light during the day.

I had heat issues with my tent at first. We just all assume at first that the light should be on during the day when really that's the worst time to be creating heat.

I now run at night and all my heat problems have been solved!!

You should also have an air cooled hood. It makes a HUGE difference. HTG's easy cool 6 inch is a great choice for the money IMO.

I would be using these high temps to your advantage until you can get it cooler in there...when life hands you lemons you take advantage of the increased co2 uptake!

When it gets to be over 90 degrees in there, one thing you can do is breathe really heavily on to your plants. Temps in the 90's allow for higher co2 uptake than in the 70's or 80's. Water more often as well...

With one hundred bucks you can probably get a better intake or exahaust fan for starters...scimping on your air circulation can hurt you bad i learned the hard way..

Go with a C.A.P Valuline fan...they are around your price range...or if you like ur intake fan the way it is, are you using insulated ducting? If not, get some its roughly a dollar a foot for the 6" one at home depot.


What did you hear about cool tubes? Ive never heard anything bad and thats what im going to be buying as well once i get some extra dough.

Good luck with your tent.

a can fan isnt that much better than any inline fan. they ALL make a shitload of noise.
What I'd suggest is buying a bigger fan than you need. 4", 6" and 8" inline fans all use pretty much the same power.
Get a bigger fan than you need and run it on a speed controller.
Slower=lower rpms=less noise.

CAP valulines are cheap. and unlike most cap products, they actually work!!!

a coolshade will solve most of you problems with heat! if you're lights off temps are 74 then with a coolshade your temps should go no higher than 5 degrees Celsius.

your plants are looking nice by the way! good job

I ran the lights 24 hrs then found the best time to have them on and off and for where they are this is the perfect time. Now I change to 12/12 cause they are growing fast.
Ducting here is almost 20 for about 3ft at all home depots iv been too. I might buy online its cheaper
i heard cool tubes dont cool as efficent as a standard fixture. Im getting a cool tube though I saw a nice one on amazon for a good price and seems like good reviews
Im going to look into the valueline I never heard of them but I did find a 6in 500cfm fan for $80ish maybe for the cooltube and another for my intake. maybe dry ice for co2 and cooling for now what do u think

Btw how safe is this site. Im always warned to use different computer

Hey i have the same tent with a 400w light. So i think you should spend your money on a used inline fan like the valueline's. At least 400cfm. So that 500cfm 6" would be perfect. Only thing is the exhaust ports are only 5"s, so i had to get a 6" to 4" adapter, just to run barely through the port and into the tent. Right at the top where all the heat is. Anyway, if you have a good exhaust fan though, there is no need for an intake, as if you just leave the intake holes open at the bottom of the tent, you create a negative pressure, and the tent pulls in all the fresh air it needs, as it sends the hot air out. Bingo, all you need. Now i personally am looking into getting more of these tent setups, so im going to have a portable air conditioner in the room to keep the temps right. But with one, just have your lights on at night, and sell your intake fans to get a powerful exhaust fan. Check out page 3 of my journal, and you can see how i set up mine. Oh, and a canopy level oscillating fan helped a good deal.

...on a second thought, i also am a fan of low humidity levels. I feel like 40 is ideal, as its still fine for the plants, but you avoid lots of mold and mildew problems. Also i hear lower humidity levels are good in flower, because it makes the buds stack up more crystals and resin.

Try this fan it blows out nice quality air I almost took it with me when leaving my moms http://mobile.walmart.com/ip/Lasko-Products-HVB-Oscillating-Blower-Fan/16503201?search_url=aHR0cDovL3d3dy53YWxtYXJ0LmNvbS9icm93c2UvSGVhdGluZy1Db29saW5nLUFpci1RdWFsaXR5L0ZhbnMvXy9OLTk4OWg/X3JlZmluZXJlc3VsdD10cnVlJl9yZWZpbmVyZXN1bHQ9dHJ1ZSZjYXROYXZJZD0xMzMwMzImcmVmPSs0MzA2MTMmaWM9NDhfMCZicm93c2Vpbj10cnVlJnBvdmlkPWNhdDEzMzAzMi1lbnYyMDMyMzMtbW9kdWxlQjEwMDExMS1sTGlua0ZDOEZhbnM: