Cool Tube vs Bare Bulb

Malevolence

Malevolence

New Member
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.
 
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.
 
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. :blsmoke:

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.
 
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).
 
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.
 
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
 
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.
 
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.
 
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.
 
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.
Click to expand...

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.
 
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.
Click to expand...

^ 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.
 
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.
 
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
 
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
 
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.
 
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
 
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.
Click to expand...

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.
 
^ 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.
Click to expand...
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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