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Thread: Controlling heat with cfls

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    Default Controlling heat with cfls

    I've got 2 plants growing in a 75x75x130cm tent, 4inch rvk extractor, cple fans inside, up til now I've been using a 300w blue spec cfl and recently added a 125w blue spec bulb too on the side, temps have been stable around 25c and humidity has never really been a challenge. As one has started to stretch and pre flower I changed the bulb to red spec for flower so put a 300w red in and a 125w dual spec to replace the side light. Now my temps are hitting 28-29c even with vents open and fan on full. So for now I've taken the 125w out and the temp settles around 24-25c. I feel like I'll be missing out if I have to leave the 125w out as there won't be as much penetration around the plant. Although it is my first grow so I'd rather sacrafice yield than risk ruining it with too much heat. Any ideas for keeping it cool other than buying something pricey to control heat?

    I've always had a passive intake through a vent hole, I have got a small 4 inch black orchid if the problem is not putting enough cool air in there, was almost against putting another fan in though due to noise.

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    May sound silly but are your circulation fans inside the tent close to the bulbs? New growers make this error some times and circulate heat from the bulb adding 3-4c.

    Failing that Id hook up the intake and bring in cooler air from elsewhere

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    Quote Originally Posted by Blue View Post
    May sound silly but are your circulation fans inside the tent close to the bulbs? New growers make this error some times and circulate heat from the bulb adding 3-4c.

    Failing that Id hook up the intake and bring in cooler air from elsewhere
    Yeh thats understandable, I don't think so though, one osci fan is above the reflector in a corner at the top of tent and a 120mm pc fan on 12v in the opposite corner on the ground. So nothing is directly blowing against the light. May have to see how much noise the B O makes and use that or sacrifice the yield this time round and work on a smarter setup next time.

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    Quote Originally Posted by AND View Post
    Try giving the CFL's a clean as dust makes them heat up quite a lot
    Yeh it doesn't take long for it to settle, wonder would 2 125w bulbs be better spread out, even though its less watt its more coverage...more bloody money to find out though lol.

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    I always liked using iron ironmans suggestion of having the light at a slight angle up with a fan behind aimed at blowing the heat up the reflector and away from the plants

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    Quote Originally Posted by Silkadin View Post
    I always liked using iron ironmans suggestion of having the light at a slight angle up with a fan behind aimed at blowing the heat up the reflector and away from the plants
    Yeh that makes sense, I've read he knows his shit when it comes to cfl's. I'll hobble through this and next time get a proper idea of how I want things from the go. Made so many changes since the beginning its a wonder they're still alive. Just had a tent in the corner of the utility room to start, now its boxed in, half the room sectioned off with plasterboard, big ass box for the rvk on a stand next to it. Had to build all this around the tent without moving it haha. All good fun though

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    Quote Originally Posted by MrCannab1sir View Post
    Yeh it doesn't take long for it to settle, wonder would 2 125w bulbs be better spread out, even though its less watt its more coverage...more bloody money to find out though lol.
    Ive got my 300w dual spec CFL in a cooltube connected to extract for seedlings, no heat at all 2 x 125w would maybe be better as its 50w less and as you say spread out

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    May look at a cool tube setup for next time if they really reduce the heat. I'll switch the main red for a dual spec and switch the 125 on too and see how that effects it, roll on 4pm

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    Well after more than a bit of fookin about I've managed in the past 30 mins to get it to be 24.9c and 51% hum at the bottom of the plant and 26c and 48% hum at the top, put 4 wet towels in so humidity at the top should creep a cple %. I put the black orchid in as a fresh intake, took the little pc fan out as it serves no more purpose than the intake, same place and doesn't turn, put a 300w dual spec and the 125w dual spec in, cranked the extraction up to 4 and here we are, hope this holds, really don't want to lose the extra light. Thanks for chipping in.

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