# Cool Tube vs Bare Bulb



## Malevolence (Oct 20, 2013)

Is there that big of a difference going bare bulb over using a cool tube? I have heard people say the glass from a cool tube blocks the light, but sounds like a bunch of nonsense to me. I am running 2 vertical cool tubes due to heat issues.


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## AimAim (Oct 20, 2013)

The glass filters out a bit of light, I read 5-10% of certain wavelengths. If you need to extract heat then you gotta have some way to suck it out. Taking the glass out of your tubes will give you a little more usable light, but your heat extraction if going to be reduced big time. If you don't have temp problems you might be able to do without the glass, still running the extraction fan without the tube will remove a lot of heat, question being will it remove enough.


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## MrMeanGreen (Oct 21, 2013)

I sold all my cool tubes when I switched to hoods, then I sold all my hoods when I switched to vert and bought all my cool tubes again doh. The moral of the story....... cool tubes are for life not just for noobs. 

I struggles to see how people manage 2kw or more of heat in enclosed space without cool tubes and direct extraction. I find with cool tubes and straight through extraction (clean air no scrubbers) my ambient room temp is only a few degrees higher than ideal and small extractor with scrubber sorts that out a treat.


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## mellokitty (Oct 21, 2013)

every room i've seen with over 10 1kw lamps were set up with bare bulb (and i've worked with 90+ in a barn), it DOES make a significant difference in side-by-side tests.

however, if your room is already set up with cool tubes, changing to bare bulbs will be more of a pain in the ass than it's worth (especially if you're running less than, say, 6 lights). 

to go bare bulb you basically want to design it that way from the get-go; you have to consider heat management for your whole room instead of immediately around your lights (we run hella fans for in/out plus a 5t a/c in the summer). if you're curious how it's done you can take a peek in my journal (link in sig) (skip forward to page 30ish to really see it in action).


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## Malevolence (Oct 22, 2013)

Right on... looks like I will have to stick with the cooltubes for now. I am running between 1050-1200w of lighting in a closet on a single 15a 120v breaker, so A/C is not possible. I could run fewer lights but obviously 3 lights in tubes is brighter than 2 bare bulbs.


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## JonnyAppleSeed420 (Oct 22, 2013)

Uv is blocked partially from the glass. Not worth all that heat from an open bulb IMO. You seem to be using about 11 amps off that breaker, that is basically the max you want to play with, too be safe. Is there any way you can cool the area you pull your air from? A/C doesn't need to be in the grow, the cool air does..._JAS_


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## Pepe le skunk (Oct 22, 2013)

With a bare 1K MH it raises the temp by 10 degrees easily. If UVB is needed use UVB florecents in combination with cooltubes because florecents run way cooler and provide more UVB anyway. 10-12% UVB bulbs anyway. Arcadia 55 watters are great.


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## 1itsme (Oct 22, 2013)

everyone i have talked to that runs bare bulbs seems to think cooltubes are totally unnecessary and block light. I have run cooltubes in vert and they definitely restrict the light a lot more than 10%. maybe 10% is blocked by the glass but a bunch goes right into the ducting as well. whodatnation, prawnconnery and heath robinson all have barebulb vert journals that are worth checking out. If you set up the fans right i don't thing heat buildup is as big an issue as you would think.


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## Malevolence (Oct 23, 2013)

That's a good point, I do notice the inside of the air duct is nice and bright. I have always read the glass from the lamp itself is designed to block UV radiation. There is a thread in the advanced section that recommends the 55w arcadia UVB florescents.

I am growing in a closet, and there is an air duct into the closet... so funny enough my temps are cooler in the summer than they are in the winter. This is because I run the a/c heavily in the summer which blows into the closet. I run heat in the winter which also blows into the closet. 

I am moving very soon, and in the new place I plan to run two 400w lamps in a larger space. My veg area will be in another room on another circuit. I will probably try my temps with bare bulb and 6" mixed flow maxfan for extraction (in addition to normal fans). With cooler temps and less electrical load, I hope to add UVB... but more important is an air purifier to catch the pet fur and dust. I may run another circuit to the garden, but it's an apartment, so maybe not. My only concern is the lamp popping and starting a fire, but I do plan to get a Flame Defender for my new garden regardless.


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## Canon (Nov 1, 2013)

Thing I've noticed about tubes is the grower.
They start out good and keep the tube clean. After about 6 mos the cleaning tends to fall way off to the wayside. Then you can scrape the shit off with your finger nail. that's when lumins go to pot.


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## 1itsme (Nov 1, 2013)

Malevolence said:


> That's a good point, I do notice the inside of the air duct is nice and bright. I have always read the glass from the lamp itself is designed to block UV radiation. There is a thread in the advanced section that recommends the 55w arcadia UVB florescents.
> 
> I am growing in a closet, and there is an air duct into the closet... so funny enough my temps are cooler in the summer than they are in the winter. This is because I run the a/c heavily in the summer which blows into the closet. I run heat in the winter which also blows into the closet.
> 
> I am moving very soon, and in the new place I plan to run two 400w lamps in a larger space. My veg area will be in another room on another circuit. I will probably try my temps with bare bulb and 6" mixed flow maxfan for extraction (in addition to normal fans). With cooler temps and less electrical load, I hope to add UVB... but more important is an air purifier to catch the pet fur and dust. I may run another circuit to the garden, but it's an apartment, so maybe not. My only concern is the lamp popping and starting a fire, but I do plan to get a Flame Defender for my new garden regardless.


For the dust and stuff (airborne bugs/mold spores...), I use a 20x20 hepa furnace filter duct taped to the back of a 20" box fan. It filters alot more air than most purpose built filters, it's cheap, and it still pretty good as a fan.


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## Prawn Connery (Nov 10, 2013)

Canon said:


> Thing I've noticed about tubes is the grower.
> They start out good and keep the tube clean. After about 6 mos the cleaning tends to fall way off to the wayside. Then you can scrape the shit off with your finger nail. that's when lumins go to pot.


^ This. Glass does filter out light - the same as water and air and all other "transparent" mediums filter out light - but the biggest problem with cool tubes is they get dirty. Dirty on the outside and dirty on the inside - and it is this that causes the greatest loss of PAR.

With a properly ventilated room or cabinet, and with a fan blowing directly over the bulbs, a cool tube makes alost no difference at all to inside teperatures or flowering results.

How do I know? I've been growing vertically for almost 10 years; I've grown with and without cool tubes, and I discovered pretty quickly that they don't have much place in vertical growing if you use a floor fan and overhead extractor fan to funnel a cool column of air over the bulbs (1200w in my case).

If anyone thinks cool tubes are such a great idea, I have a double-length glass tube with fittings at each end for 1200w (600w each fitting) I'd be happy to sell. It's been sitting in its box for five years and I have no intention of ever using it again.


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## SnapsProvolone (Nov 17, 2013)

If a cooltube was used with a double ended lamp you could consider the tube as equivalent to the blub jacket.

Just need a socket that will make this work.


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## Nizza (Nov 17, 2013)

the only real purpose i see a cool tube being used for is on a sealed big grow.
the tubes are on one channel to pull heat out of the grow at the source
and there should also be an intake filter, to keep the insides clean! make a filter box so it's easy to change the filters, saves you a fuck load of time cleaning things.

now that the heat is mostly taken care of, you won't need as big of an A/C unit, and on top of that you have less heat evaporation transpiration issues, making the dehumidifiers work less hard. Hopefully at this point an a/c on dry cycle will keep things spot on, and the dehumidifier won't run

don't forget the filter on the a/c unit, this will help clean airborne dust and particles, and prevent them from getting on the leaves, and cool tubes.

I understand how a cool tube could be used effectively, but on a small op it is REALLY unnecessary, and i wouldn't plan on ever using cool tubes unless they were on there own loop, and properly maintained


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## dubcoastOGs (Nov 17, 2013)

So i've been told having a piece of glass inbetween your bulb and the canopy can cut the lumens down by up to 30%. I can't really say if this is true or not, I could see it making sense, But I stopped using the glass on my sun system hood. Still don't have a temp problem. 

edit: nm, I just finished reading the rest of the thread, lol


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## Prawn Connery (Nov 18, 2013)

I dunno about 30 per cent, but the more glass you can remove, the better. All glass filters out some light - even the glass on the bulb itself.

You will read on some of the newer HID lamps that many now use low-iron glass to increase lumen output. Iron in the glass makes it stronger, but also gives it that green tint which filters out light.

Cool tubes can have their place in horizontal grows, IMO, because they allow you to get the lamp closer to the plants without burning them - thus increasing yields (offsetting the small reduction in light that is filtered by the extra layer of glass). But in vertical grows, heat rises and doesn't get trapped under hoods. A good floor fan (as explained) will also duct most of the heat away.


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## 3ATP+O2 (Nov 19, 2013)

I run my inline fan through a cool tube but disconnect the intake side inside the tent. I cut a 6 " intake vent in the tent and used a 10' section of flexible 6"venting and spray black as much of it as i could. this keeps my 6x4x7 tent between 68-77 F at all times. only issue is i live in low humidity area so i run a humidifier with lights/fan on. my humidity is between 37-66%. this keeps the bulb cool and allows fresh air into the tent


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## banks dank (Nov 22, 2013)

Imo Cool tubes have a place in closet grows
Or confined areas...a 5x5 closet for example
Would be perfect for 1k cool tube...

Basically small area where heat is a big issue go cool tube.


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## beuffer420 (Nov 22, 2013)

banks dank said:


> Imo Cool tubes have a place in closet grows
> Or confined areas...a 5x5 closet for example
> Would be perfect for 1k cool tube...
> 
> Basically small area where heat is a big issue go cool tube.


gotta agree for years I ran 3k in flower with raptor hoods. About 4 months ago I bought 3 new style raptors about a week later I saw my buddies garden that was all cool tubes. My jaw dropped at the temp difference from the raptor hoods to cool tubes. Plus if had a doob I was smoking and blew it into my raptor hoods, the smoke just swirled around for a good min before it was taken out. Long story short I bought 4 8" cool tubes so I an extra 1000 watts went into my room and my heat changed zero from the extra 1000 because of the cool tubes ability to move air better than a square hood. My plants are happier IMO because the light isn't distributed down with excessive force towards the plants. I bent the wings almost straight out and it throws a very nice pattern. Not one dark spot in my room.


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## Prawn Connery (Nov 22, 2013)

^ We don't use hoods in vertical growing - that's why we don't need cool tubes.




banks dank said:


> Imo Cool tubes have a place in closet grows
> Or confined areas...a 5x5 closet for example
> Would be perfect for 1k cool tube...
> 
> Basically small area where heat is a big issue go cool tube.


I run 1200w in a 4'x4' closet and, as I said, I don't use cool tubes. Don't need to. And I grow in some pretty hot Aussie summers. Good ventilation is the key.


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## banks dank (Nov 22, 2013)

Prawn Connery said:


> ^ We don't use hoods in vertical growing - that's why we don't need cool tubes.
> 
> 
> 
> I run 1200w in a 4'x4' closet and, as I said, I don't use cool tubes. Don't need to. And I grow in some pretty hot Aussie summers. Good ventilation is the key.


For the sake of knowledge let me ask this...

Why are there such thing as cool tubes if bare bulb works so easily? Whats the main point behind it? What was the reason such a design was created? 


Imo I would say watt for watt you could produce more with cool tubes in a 5x5 then normal reflectors.

Try and stick 3k's worth of hid lighting in a closet without a cool tube setup and you will see its a heat battle from hell. Cool tubes design is built on the principle to be all about heat control. 

someone please correct me if im wrong but if I remember correctly u have to have a closed system to run co2 Effectively so your lose that option.

Again thats just my opinion Not arguing...


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## Prawn Connery (Nov 23, 2013)

Cool tubes serve one purpose: to duct heat directly away from the lamp. You can do that without a cool tube. Cool tubes were originally designed for horizontal growers battling heat under their hoods - that's why the first cool tubes had reflective material on one side.

You can try running CO2 in a closed system, but plants respirate during the lights-off period - when they need oxygen - so you'll find most CO2 growers only use gas during times of photosynthesis.

As for heat build-up in a closed system, all a cool tube does is duct heat away from the lamps and recirculate it - the hot air simply gets drawn back into the cool tube to be heated even further. That's why closed-system grows usually have aircons, dehumidifiers and other environmental controls.

Now, if you'd care to share the details of your 5'x5' 3000w grow, I'd love to see it! I'd also love to know how many watts per gram you are yielding.

Then we can compare it to my system


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## banks dank (Nov 23, 2013)

Prawn Connery said:


> Cool tubes serve one purpose: to duct heat directly away from the lamp. You can do that without a cool tube. Cool tubes were originally designed for horizontal growers battling heat under their hoods - that's why the first cool tubes had reflective material on one side.
> 
> You can try running CO2 in a closed system, but plants respirate during the lights-off period - when they need oxygen - so you'll find most CO2 growers only use gas during times of photosynthesis.
> 
> ...


For the sake of knowledge I said...
Dont turn this into a pissing contest


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## banks dank (Nov 23, 2013)

What are u talking a cool tube recirculates hot air? Its intake is supposeb to be conntected to an area where it can draw in cold air...that would be pretty damn stupid to have a "recirculating" cool tube...


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## MedicatedGrow (Nov 23, 2013)

I use a air cooled hood now before I didnt but I probably dont need it considering 20-40F temps now

I have one vent hanging out the window sucking in that super cold air and a 240CFM fan pulling the air out of another vent and the air comes out super cold not warm in the slightest sense


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## Prawn Connery (Nov 23, 2013)

banks dank said:


> What are u talking a cool tube recirculates hot air? Its intake is supposeb to be conntected to an area where it can draw in cold air...that would be pretty damn stupid to have a "recirculating" cool tube...



Then why did you mention closed systems?



banks dank said:


> someone please correct me if im wrong but if I remember correctly u have to have a closed system to run co2 Effectively so your lose that option.


You wanted someone to correct you if you were wrong, but now you don't like the answer 




banks dank said:


> Imo I would say watt for watt you could produce more with cool tubes in a 5x5 then normal reflectors.
> 
> Dont turn this into a pissing contest


You claim "watt for watt" your system is better, but you don't want to compare it to someone else's system. Do you think anyone is going to believe your claims if you're not prepared to have them tested?

Same goes for your 5'x5' 3000w system: if you prove to us all how well it yields, then you might be in a position to tell us all what does and doesn't work.

In the mean time, I already know what does and doesn't work in my system - because I've been doing it a long time and have the results to prove it.


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## Prawn Connery (Nov 23, 2013)

MedicatedGrow said:


> I use a air cooled hood now before I didnt but I probably dont need it considering 20-40F temps now
> 
> I have one vent hanging out the window sucking in that super cold air and a 240CFM fan pulling the air out of another vent and the air comes out super cold not warm in the slightest sense


A friend of mine runs a 3000w commercial grow and he runs air-cooled hoods, as he doesn't have the layout (or patience!) to grow vertically. I convinced him to take all the glass covers off his hoods and now he's yielding about 25oz per 600w bulb (about 125oz per grow).

His room temps are the same, his yields are higher (you'd be surprised how much light gets absorbed through a layer of not-so-clean glass) and all he has to worry about now is not letting his buds grow into the lights - a little extra tying down, that's all.

Now, some people may be forgetting this is the "Vertical Growing" forum, so I'll just remind everyone the question is: "Cool Tube vs Bare Bulb" - not "Cool Tube vs Horizontal Hood".


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## banks dank (Nov 24, 2013)

Prawn Connery said:


> Then why did you mention closed systems?
> 
> 
> You wanted someone to correct you if you were wrong, but now you don't like the answer
> ...


Let me reiterated that the post are my opinion. Its my opinion.
And you get all hurt when someone is asking questions and u answer like your the final authority. 

So cool tubes are completely useless in growing then? 

Hmm thats weird...i wonder why they are sold since they have no benefit at all to bare bulb.


Since you know everything tell me why there is such thing as a cool tubes if they dont work any better than bare bulb? school me bro. 

Side by side I still think u could run more watts than a bare bulb w a cool tube and honestly bro if I had the cash and time I would just to show you that I could.

Cool tubes can be utilized for a closed system. Im unsure why u think thats wrong. Sure u can have a closed system bare bulb but obviously heat will become an issue. That when cool tubes come in...
In Grow room design anything can be done...question is how practical is it. 

Imo any light that was taken away due to a "dirty cool tube glass" would be compensated in the close distance that u could have the bulb growing to the plants...








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## banks dank (Nov 24, 2013)

...............


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## Prawn Connery (Nov 24, 2013)

You're asking the same questions I and others have already answered. And it's not that I'm hurt (I really couldn't give a shit), it's that I don't really have a lot of patience for people like you who ask questions "for the sake of knowledge", then quickly dismiss the answers and insist you know better - even though you have nothing to back it up.

You're entitled to your opinion - and I'm hardly the final authority - but I'm not wasting my time answering the same shit over and over again for the sake of your ego.



banks dank said:


> Cool tubes can be utilized for a closed system. Im unsure why u think thats wrong. Sure u can have a closed system bare bulb but obviously heat will become an issue. That when cool tubes come in...



^ There you go again with your "closed system" - do you even know what a "closed system" is? Where do you think the heat goes in a closed system? Do you know anything about physics and heat conductivity? Do you even know the difference between horizontal and vertical growing and why we do it; why cool tubes don't have the same place in vertical growing as they do in horizontal growing? No, I didn't think so. Good luck with your grows.


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## kinddiesel (Nov 24, 2013)

there is a huge difference in cool tubes and open hood . in veg you will notice the mh bulb will kill your eyes in a open hood spreads very wide can do a shit load of plants off 1 bulb and in a cool tube its more direct to the plants. but does not look as bright. hps there also a difference. slight difference. I like to use flat hoods for bulbs work a lot better then cool tubes the flat glass ones not round. spreads the light more even to the plants. the cool tubes seams to be a few dead spots. I used to do nothing but cool tubes then I changed to cool hoods. with flat glass. . now who can handle all that heat from more the 1 open hoods ???? not me pump a 50 thousand btu ac unit @ 3 dollars an hour


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## thecoolman (Nov 24, 2013)

In my experience during cool whether and with good fans air cooled bulb sealed room systems save big on the ac bill. Once it warms up a bit bare bulbs are much better and with the added benefit of a neater room with less cluster fuck..


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## Prawn Connery (Nov 24, 2013)

kinddiesel said:


> there is a huge difference in cool tubes and open hood . in veg you will notice the mh bulb will kill your eyes in a open hood spreads very wide can do a shit load of plants off 1 bulb and in a cool tube its more direct to the plants. but does not look as bright. hps there also a difference. slight difference. I like to use flat hoods for bulbs work a lot better then cool tubes the flat glass ones not round. spreads the light more even to the plants. the cool tubes seams to be a few dead spots. I used to do nothing but cool tubes then I changed to cool hoods. with flat glass. . now who can handle all that heat from more the 1 open hoods ???? not me pump a 50 thousand btu ac unit @ 3 dollars an hour


Again, you're talking about horizontal hoods. Most vertical growers don't use hoods.

The theories applied to horizontal and vertical growing are different for one main reason: because heat rises. In a horizontal system, you generally have a hood (or cool tube) above your plants and the rising heat gets trapped under the hood unless you duct it away. Open hoods can also be ducted at each end, and do not need to be sealed to achieve this.

In a vertical system, heat simply rises and gets ducted away by the exhaust fan - it never gets trapped under a hood. Plus, you generally have a floor fan blowing directly on the bulbs which ducts heat away from them and cools them with a column of moving air - just like an air-cooled motorcycle engine uses wind ducting to conduct heat away.

It comes down to basic physics: you need to understand the physics before you can start to understand why some things work and others don't.

Same goes for "sealed rooms". There are two types of "sealed room" - one that is completely enclosed and recirculates the same air that is used for cooling the bulbs, and one that has the grow section sealed but draws cool air from outside through ducting and cool tubes, and then expels the hot air outside - the lighting system is not sealed inside the room, but runs a second ducting circuit. In such cases, yes, cool tubes do their job. But in an atmospheric system, as long as you have good ventilation and don't have heat-trapping hoods (which you won't in a vertical system), you really don't need cool tubes. 

And as some vertical growers are already discovering, there is an optimal distance for plants to be away from the lights that is a trade-off between maximum PAR and light spread: giving max PAR to a few plants packed closely around a bulb may not give better yields than spreading the light over a larger area with slightly less PAR. It's all about finding the correct balance - and that usually comes with trial and error (otherwise known as "growing experience").


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## Prawn Connery (Nov 24, 2013)

See the exhaust fan above this bulb? It is sucking heat directly off the bulb. The lower bulb is being directly fan-cooled. Do you see how close the buds are to this lamp? Do you see any burn marks or bleaching of the buds? This system works and has worked for almost 10 years, yielding well over 1g/w each and every grow.


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## nickelz419 (Nov 30, 2013)

Any tips on taking the glass off? It is glued on......i wanna go bare 

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## Prawn Connery (Nov 30, 2013)

Is there not some way to remove the lamp plug and chord by undoing a few screws? That's how my cool tube is designed. It's hard to see from your pic.

That said, this is a great example of the amount of light lost through cool tubes. Just have a look at how clear the plants on the left are, where there is no glass, and then have a look at the plants behind the glass - see how dirty and opaque that glass tube is? This is exactly what I and others have been talking about. You can't argue with your eyes - have a look:


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## nickelz419 (Dec 1, 2013)

Fully nude!

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## nickelz419 (Dec 1, 2013)

Thanks bud.

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## Ilovebush (Dec 1, 2013)

Just ma 2 cents...I'm gonna agree with bare bulbing being the way to go unless space is tight.


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## Prawn Connery (Dec 1, 2013)

nickelz419 said:


> Fully nude!


Way to go, dude! You won't regret it - just wait and see.


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## hyroot (Dec 2, 2013)

Prawn, I was about to buy an 860w CMH. But my buddy that loaned me t5's isn't growing anymore. He is trying to give me his 1000w's. To be paid for later with trading for buds. If I run a strong fan on the floor and an inline fan above 1 1000w. Run that inline fan to vent outside. Should that keep the 1000 cool enough bare bulb? He has cool tubes too. I'd rather not run cool tubes. But if heat is an issue I might.


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## Prawn Connery (Dec 2, 2013)

Shouldn't be a problem. 1000s can get hot, because they produce almost as much heat from one bulb as two 600s, but inline cooling should take care of it. You may need to space your plants a little bit further away from the bulb initially to see how it goes, as there will be a slightly larger concentration of heat from the one bulb (1000), instead of being split over two bulbs (600s), but plenty of vertical growers use 1000s to great success.

If worse comes to worse, you can always try the cool tubes. I don't discourage people from using them, it's just that in my experience - and in my set-up - I don't see a need for them. But I also understand that sometimes people just have to try things for themselves.


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## Alishia541 (Dec 4, 2013)

I will try this.


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## legallyflying (Dec 10, 2013)

Just finished up a run with 18 1k bare bulb vert grow (trees). 

I would never ever never ever fucking ever fuck with hoods, fans, ducts, all that shit. 

Small desk fan blowing up under each bulb and then the temperature control system of your choice. Lots of AC or big inlet/outlet on temp switch. 

WAY cheaper, better light, no fucking dirty glass, no noisy fans, no tins of duct running all over the place and dripping in the winter .

Cons..you can burn yourself on the bulbs. More heat in the room.


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## F1_Grower (Jan 22, 2021)

legallyflying said:


> Just finished up a run with 18 1k bare bulb vert grow (trees).
> 
> I would never ever never ever fucking ever fuck with hoods, fans, ducts, all that shit.
> 
> ...


Well said and 18 hanging must of been a large space,, what was your grow size & ambient temps outside grow room? Did you run Co2? And Inlet /outlet on temp switch. As in min timerm bc I plan running co2 which higher temps are formidable right so going bare from 72 temos hooded to bare 82 ok right? Im sorry, im in midst of setting up own vert grow and only reason wanted a cool tube /reflector combo is that im vert growing 180degree only in a bath tub so not 360 and having heat exhausted uo through bathroom exhaust vent with a 6 to 4 reducer and I've heard an 8 to 6 reducer with Honeywell grill cut out works well too from RIU Club 315 CMH vert group


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## F1_Grower (Feb 11, 2021)

F1_Grower said:


> Well said and 18 hanging must of been a large space,, what was your grow size & ambient temps outside grow room? Did you run Co2? And Inlet /outlet on temp switch. As in min timerm bc I plan running co2 which higher temps are formidable right so going bare from 72 temos hooded to bare 82 ok right? Im sorry, im in midst of setting up own vert grow and only reason wanted a cool tube /reflector combo is that im vert growing 180degree only in a bath tub so not 360 and having heat exhausted uo through bathroom exhaust vent with a 6 to 4 reducer and I've heard an 8 to 6 reducer with Honeywell grill cut out works well too from RIU Club 315 CMH vert group



Its comming along, not sure which is better bare bulb vs cool tube
too much mixed specs, but heat 75 to 85 F, RH 50 to 65%


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## BiT_de_H (Nov 8, 2021)

banks dank said:


> Imo Cool tubes have a place in closet grows
> Or confined areas...a 5x5 closet for example
> Would be perfect for 1k cool tube...
> 
> Basically small area where heat is a big issue go cool tube.


 I woudnt like to see how much it ll be in my 5x5 tent. I'm running 1000w hps sf4000 and to other little qb 135 watt real wattage plus 3x 42 led neon bar


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## luxborealis (Nov 12, 2021)

F1_Grower said:


> View attachment 4822786
> Its comming along, not sure which is better bare bulb vs cool tube
> too much mixed specs, but heat 75 to 85 F, RH 50 to 65%



The only benefit here is if you can't manage the heat otherwise. A glass tube absorbs a significant percentage of the photons trying to pass through it, and all traces of UV which are able to pass through the bulb are also lost.


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