Inline fan isn't cutting it

Discussion in 'Growing Marijuana Indoors' started by WACaregiver, May 6, 2011.

  1. For the record, I have tried registering on these forums for like a year and for some reason, my account never gets activated to the point where I can ever post. Anyways, this is my setup.


    Tent: 2 x 4 x 5.5
    Exhaust: 170 cfm HTG brand inline through 4in ducting
    Intake: 12in desk fan blowing through intake slat
    Circulation: 10in desk fan pointed at plants
    Light: 400watt Sunmaster Warm Deuxe
    Hood: HTG 6in Eurocool vented hood

    As is, I'm getting temperatures averaging 74*-81* during the day which I don't have a problem with but my hydro reservoir in the tent has been climbing to the mid 70's during the mid day. I would like to drop the average temp 5*-8* so I won't have to worry so much about my water temps. I could use some suggestions so here is a little more info on my limitations.

    1) I'm not on a super tight budget but running out and spending a few hundred dollars isn't all that possible for me right now. I would prefer not to dish out a bunch on this one.

    2) My apartment doesn't have AC so the ambient temps in the room get a little warm. The grow room is also my bedroom and I am comfortable with the current temperature. I would rather increase the efficiency of my ventilation system than sacrifice a comfortable bedroom temperature.

    3) I'm probably not going to be using a carbon filter. The stress on the fan isn't worth it when battling temps so I'll probably be using ONA gel for odor control.

    4) I can't upgrade to a 6in fan. The holes in the tent are 4in and I'm not willing to cut the fabric.

    5) I can't take my reservoirs out of the tent. I'm doing a 2 tub 14 gallon DWC. I'm brainstorming a low to the ground aeroponics system with a remote reservoir but that won't see daylight until next harvest.

    I've played with a few ideas already. The cheaper ideas would be ideal, but I don't know if they would work or not. A cheap fix that doesn't work is a waste.

    A) Fit 6in computer fans to the hood, use the inline fan to just vent the tent. Would cost about $30 but I don't know if it would work.

    B) Install a 4in duct booster fan at the end of my duct work. $15-20 for a cheap booster fan. I was under the impression that these are more for assisting air through long straight sections of pipe, not assisting with suction in a small area.

    C) Buy a portable air conditioner for the room. I can't buy a window unit because I have sideways sliding windows. The cheap AC units that use water circulation are out of the question. They are a pain. The cheapest decent portable AC runs $300+. This is my last resort.
  2. Loose the intake fan, use a passive intake
  3. maybe get get a 6" inline, get a 4"-6" connector, hook the 4" side to your out-take, 6" to your new inline.

    no need to cut fabric but not sure how well this would increase exhaust because its still sucking through a 4" hole, but it would up t he cfm quite a bit so I wouldn't see it not working
  4. #4 HookdOnChronic, May 6, 2011
    Last edited by a moderator: Mar 15, 2016

    These guys got to it before me. I was thinking you should do both. No need for an intake fan thats just waisting electricity. Maybe try to put it in your ducting to help keep the air flowin.

    I'm currently running a 6" fan with 4" ducting/hood to cool my 1k. Hell I've used an 8" fan on my 4" ducting before. Lol. Just smoke a bowl, go to home depot and get inventive. Thats what I do
  5. #5 Cannaculus, May 6, 2011
    Last edited by a moderator: May 6, 2011
    Your air temps are fine, so address the real issue with the water temperature. What are you using for a reservoir? Use a cooler for good insulation and if the temperatures get too high you can add frozen bottles of water.

    Just noticed you're not going to have a carbon filter? I'm not sure how well Ona gel works for masking the scent of flowering plants completely, but I wouldn't rely on it. Upgrade your inline fan to 300-400 cfm, add a carbon filter and you won't have to worry about any smell leaking out until the filter is used up. It'd help your temperatures too, especially since there's no AC at your place, what's going to happen with that 170cfm inline when your ambient temps hit 80+ F in the summer?
  6. I put this thread on Yahooka and got the idea to invert my light cycle. I am flowering in 2 weeks so that's when I'll set my lights to be on during the night and off during the day.

    I'm not too concerned with the odor of my grow getting out of control. My setup is all 100% legal (as my user name suggests) and my landlord has already given me a letter of approval. I am just doing it so my room doesn't constantly smell like dank marijuana, making my clothes smell like marijuana, making me constantly smell like marijuana. Odor control is convenience.
  7. #7 Russy, May 7, 2011
    Last edited by a moderator: May 7, 2011
    Sorry your on a budget , but you need a higher CFM fan . Period.

    170 CFM is weak even for a 400 watt light... even a cheap 4" Inline is usually around 400 cfm, which would be a major difference !

    Your temps dont seem all that bad, I wouldn't panic until your hitting 90+ consistently


    A brand new 440 CFM 4" inline is around 100$ , a lot cheaper than an A/C , I dont know much about Hydro growing, perhaps you need some sort of water chiller for your res temps, but really only guessing on that part.

    Really, your temps are fine for now !
  8. I don't see why frozen water bottles in you res wouldn't work but it also sounds like you just need a bigger fan you can buy duct pecies to neck up a 4" to a 6" so like said before no need to mutilate your tent. Also booster fans that you can buy at home depot for 30$ will always help move more air the faster it's out of the tent the better off your temps will be especially if your only looking for a few degrees difference just pull the air out quicker
  9. Is it safe to have your roots touching something that is at freezing temperatures? I'm no botanist but I imagine it would hinder growth and possibly kill roots.

    I read tons of reviews before buying my fan. There are a lot of super high CFM fans out there at a low price but when tested they very rarely pull even half of the air they are rated for. I put money into a fan that I knew was going to pull 170 all the time and not crap out on me, and for my space, 170 is plenty sufficient even with a 400 watt. Plus, spending $600 on a water chiller would be pretty retarded considering my entire setup is home made.

    I've been reading a bunch of Jorge Cervantes stuff on temp control and he advocates a higher temperature at times. I'm still within the "safe" range but am now kind of interested in seeing the results of keeping them in the hotter range. Growth has been outstanding and the roots all look healthy. Guess high temps aren't a problem if they don't result in other problems.

Share This Page