# How necessary are the cool tubes?



## kamut (Mar 23, 2012)

Contemplating a V SCROG with 2 1k bulbs (adjustable down to 600w) in the center, surrounded by 8 plants on 8 vertical screens. I have a 8" exhaust duct that I could put above the "hole" in the middle of the garden and suck heat out that way-or do I need to put some cool tubes around these bulbs? 

Just wondering how necessary the cool tubes are or how many degrees cooler they can keep things?


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## onlybuilt4 (Mar 24, 2012)

They're not necessary unless you are in such cramped quarters that you can't keep the plants at a reasonable distance from the bulb, either by placement or by SCROG/other training.


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## matt7835706 (Mar 24, 2012)

I ran a test on the heat in my new room 3 x 3 x 8 ( not a tent )with my 1000 watt and after 15 minutes with no cooling or fans the temp was at 48 degrees celsius, that's 118 F so knowing that im for sure using a inline fan and cooling the light also I used a 250 watt light in a smaller chamber and had a fan blowing in the tube on the lamp and it was still boarder line, I was always around the 25 C -26 C which again is around 78 F. Food for though, but test your space and see what would be best before the plants are in.


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## fred flintstoned (Mar 25, 2012)

I think 2x1000W will definitely need cooltubes. You're talking about serious radiant heat in a very confined area. Some people may tell you to simply put a fan under the bulbs to blow the heat away. Seems good in principal but in practice, not so effective with 1000 watters. The heat doesn't simply disappear, it's still in the room. You'll have to be dialed in on ventilation.
A fan blowing up will help, but not near as much as aircooled lights. I've tried it both ways and found a combination of the two works perfectly. While the cooltube carries away a lot of heat off the bulb, the fan helps keep leaf surfaces much cooler. You'll have to watch out for leaf dehydration, so keep the fan speed somewhat low.
Are you planning on stacking the bulbs or hanging them in a stadium arrangement? Stacking 2x1000W will grow some enormous trees if you have the overhead space. You'll probably need about 10 feet vertical clearance. Doubt you'll be able to fit 8 plants though, more like 4 or 5 monsters that are about 3 feet wide. In a stadium setup, you can probably get 8 plants in there. I think this stadium setup would work well with 2x100W. Although I'm curious how stacked 1000 watters will work, I can't see the advantage over 600W in a small confined space unless they're spaced in a wider circle. With the extra distance you'll lose the light intensity advantage of the closer 600W bulbs. Maybe you can prove the theory, it will be interesting to watch.
I grow with 3x600W in an oval configuration and get 10x 5 footers in there for each bank of lights. It's still kind of tight so I think I'm going to veg another week and flower eight next time.
Hope this helps,
Fred


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## snowgrow19 (Mar 25, 2012)

onlybuilt4 said:


> They're not necessary unless you are in such cramped quarters that you can't keep the plants at a reasonable distance from the bulb, either by placement or by SCROG/other training.


I agree. How big is your room going to be? That will be the deciding factor a to whether you need a cool tube or not.


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## polyarcturus (Mar 25, 2012)

well IMO a 1000w regarlees is gonna need direct air cooling to get the plants close and any co2 environment needs air cooling unless you like to spend cash on elec for AC. otherwise if you are what i call naturally aspirated no tube is best(400 or 600 w) just up the air movement in the room, exhausting 5-10x a min. plus running a 400 without glass in the way is big difference, as far as the reach of the light


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## Clown Baby (Mar 25, 2012)

depends on the space. If it's a big room and the heat can dissipate a bit, you'll be fine.
In a tight box/tent thats just the size of your grow, you might need to break them out in the summer.

Cant hurt to keep em handy... I bought a hydrofarm 6" colltube on craigslist for 25$ that i keep for backup.


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## RetiredMatthebrute (Mar 26, 2012)

why are you using 2x 100w lights adjusted down to 600w? why not just use 2 600w lights?

i only ask because word on the street says running a 1000w bulb at 600w will reduce the life of the bulb and a 600w bulb will put out more lumens than a 1000w bulb run at 600w 

may want to look into buying some 600w bulbs to run at 600w and then some 1000w bulbs when your ready to increase the lumen output. 

im not a ;light expert just something for you to look into, might be worth it


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