tent extractor fans

when i put my extractor fan on it kind of sucks the tent sides in a bit, i have the fan sucking air out the top, and got just some tube winding out the bottom with no fan, went inside and closed it, and you can feel it sucking out the top, you can feel air coming in the bottom but not quite as fast, the duct is the same size coming out the top and the bottom, am i going to have to buy another fan for blowing in?

Negative pressure inside wont hurt it. At least not as far as I know.
but it could put strain on your fan.

yeah i guess, just thought about it and can't see any reason, i was thinking lack of oxygen before but it will still be getting enough fresh air in i guess.

yep its fine mate, same thing in my budbox, as long as you can feel plenty of fresh air being drawn in thru yr passives, otherwise u'l be creating a vacuum in the tent and greatly reduce co2 to yr plants, do u you keep all yr intake flaps/ports fully open? If u'v got too much extraction u can buy fan speed controllers to slow yr fan down, theyre useful if yr tent is in a cold place during the cold months when too much cold air is sucked in and chills yr plants.

no i just got the flaps closed at the moment, but what about at night this will let light in, or do most people not run fans at night? but would have thought good air was needed at all times, my tent is actually slightly too hot at the moment but might buy one of those controllers for when winter hits if its an issue

well both my veg and bloom tents are in a huge dark cupboard so i keep all the intakes open and dont need to worry about light getting in. Yea u need air exchange 24/7 especially during flower to prevent mould and when yr light go's off humidity often rockets so u need the extractor going all the time, what tent are u using? I assume it has a round intake port as well as the flaps?

got a small budbox just the other day and love it, yeah its got 1 round part and two flaps

What tent do you have??

yea i got budbox small for veg with 2x125w envirolites and budbox xl with 600w hps in cooltube for bloom. the round intake port will allow plenty of air in fine. What size extractor u using?

5 inch fan and got a 250hps which i had from my last grow, my temps range in the 80s, but got no other fans inside at the moment, was going to get a few clip on fans and see if i can direct the hot air straight into the duct, already got the duct at the end of my reflector facing the light, was thinking of also chaning the position of the bulb so that its on the same side of the reflector as the duct.

why not swap yr reflector for a cooltube? You can hook up that 5" duct u got by yr current reflector straight into one side of a cooltube, i cool my 600 with a 5" fan drawing thru the cooltube, average temps 75-80. used to have a 250 in it and could have the light 4" from the tops of plants! 8" with the 600w! It would give u much more vertical usable growspace, and reduce yr temps at least a few degrees.

i thought you had to have extra holes for that, the cool tube has two connecting parts right, so your saying extract one side and leave the other passive right? don't know why but didn't think you could do that but yeah think i might do that, i need to buy a mini clip on fan anyway so i'll try my kind of ghetto cool tube and see if it makes much difference, because it'll be getting cooler soon anyway but if not think i'll buy a cool tube, might buy one anyway if you can get the plants that close, cheers for all the help

no u wont need any extra holes or intakes, i run my cooltube a little differently, i have my 5"rvk fan mounted directly to my c/filter using a fast clamp and the c/filter and fan assembly is mounted to the top of the tent, sucking air from the growspace thru the filter and out the fan, then a length of duct from fan down to one side of my cooltube then another length on the other side of cooltube straight out the exhaust port at the top. If u mount a cooltube in place of yr reflector and hook up that sucking 5" duct leaving one end of the cooltube open u would basically be doing what your doing already sucking heat away from the lamp only far more efficiently, the cooltube would act like a funnel channeling ALL the extracted air via yr hps, rather than some air from the lamp and some from the growspace, id reccomend attaching yr duct to the end of the cooltube that has the E40 lamp fitting, because the inside of the cooltube can get dusty very quickly with all the air being pulled thru it (my air is filtered via c/filter before it reaches cooltube solving that problem) this way u can regularly take the lamp out and dust the inside of the cooltube and change yr lamp without removing the duct, u wana keep that glass clean because u do lose a very small percentage of lumens thru the glass (but being able to get it much closer more than makes up for it) and u dont wana add to the lumen loss with dirty dusty glass, i still obsessively polish my tube every 2 or3 weeks inside it and out. In a small budbox yr 5" extract fan will be more than adequate to cool yr 250, extract air and draw shitloads of fresh air in, i do it with a 600w in a xl budbox.

cool, what about when it gets colder though, i might need my room to be slightly warmer, will the light still provide some heat or is it the same of my room now, i guess i'll have the heating on but might not want it on all the time or could just switch back to my normal reflector. gonna get oner off ebay they look pretty cheap.

yea should be fine all year round. U'l still get some radiant heat escaping thru the glass even with just a 250 so that should be plenty to keep them warm, also adding clip on/ocsillating fans generally tends to increase temps slightly in small spaces, this is because they mix all the air together warm and cool and normally make temps rise slightly but will also make a more even and consistant temp across the whole room, and strengthen yr plants no end. In winter u can move the light closer if they arent getting sufficient warmth but try not to get any closer than 4 or 5 inches to the tops as iv found any closer bleaches all the green out of the tops, or u can slow yr fan down with a speed controller. Of course tho when starting seedlings or clones u want the light fairly high around 2.5-3' from the plants to prevent stress and gradually bring it down say an inch every other day til u reach a happy medium between light intensity and temps.

how much are the cooltubes on ebay? Did u get the budbox from ebay?

got my budbox on progrow for 64 cool tube on ebay was best offer and i lost, was an idiot and put 29.99 lol was 35 but, think there is another but its buy it now price is is like 39.99 so might just buy that instead of having to wait 6 days with that best offer thing.

thats uk pounds yea? That is pretty cheap, i paid 60 for my cooltube 3 years ago, it was still a fairly new thing then. Got my budboxes a year ago they were 90 for the small and 130 for the xl but got them both for 200 with a bit of discount.

yeah pounds, the cool tubes are like 50 or 60 on hydro sites

yea i think they are 49 at growell where i go, im lucky to have one of their shops near me. Anyway let me know when u get it, i predict yr temps should be about spot on with it. I assume yr 5"fan is an rvk yea? Feel free to pm me if u got any questions.