Cool tube vs. bare bulb test, just for kicks

[flat9]

So I got curious and wanted to know what kind of light loss to expect in terms of lux if I went w/ a bargain brand cool tube (Apollo Horticulture) instead of bare bulbs. I know I know, everyone says cool tubes suck, but had to verify it for myself, especially in terms of cooling costs (will explain below).

Okay so I fired up a 600w HPS (also Apollo Hort bargain brand) w/ a lux meter. Let the bulb run about 5 minutes and then took a measurement w/ my meter. I tried to keep the meter at level height w/ the bulb and also about 1 foot away, though obviously there was some variance due to not holding it perfectly in the same spot. Typical measurement was about 660 lux, and the range (as my hand moved ever so slightly) was 620 to 700.

Then waited about a half an hour w/ bulb off, turned the bare bulb on for 5 min, and did the bare bulb test. Typical measurement about 850 lux, with the range about 800 to 900.

Under the most favorable (to the cool tube) measurements (700 vs 800, respectively), the bare bulb was about 14% brighter. Under what I'd call the typical measurement (660 vs 850), the bare bulb was about 29% brighter. Big difference!

My thought was that if the difference weren't so huge, I could envision scenarios in which the extra watts required to keep the room cool w/ bare bulbs could be offset with more light via cool tube. Assuming that it would take at least nearly an extra 100 watts (thinking 14% more power x 600 watts), well, seems pretty simple to just add some more extraction fan power (you can go from roughly 500 cfm to 1000 cfm with an extra 100 watts) and call it a day. So I'm officially convinced, cool tubes blow.

Two caveats: lux is not par -- who knows which part of the spectrum gets blocked by curved glass. And maybe that bargain brand cool tube blocks a lot more light than what else is out there...

 

[farmari]

I'm going to take a guess that the loss would be even worse if testing at an angle rather than straight 'under' the bulb too, (not sure how to explain what I mean) assuming that the loss is going to be worse where the light is passing through the glass at an angle rather than straight through.

 

[flat9]

Good point... I didn't test this.

 

[flat9]

Forgot to mention, lux numbers posted above are in hundreds (so 800 is actually 80,000 lux).

 

[DamnUglyDogE]

Well done Sir....

 

[Stereotypo]

Always wondered how much of a difference the cool tube would make.

Thanks!

 

[Coconutz]

I have a 1k gavita de at 36" and a 1k blockbuster with glass at 24" and the gavita covers more area and is far brighter than the blockbuster.
The plants grow healthier, taller and stack more nodes being further away from the gavita.
I always have to clean my glass hoods. Its ridiculous how dirty they get!
I also have a blockbuster without the glass with an old 600 and it seems just as bright as my 1K with new hortilux under the glass.

 

[justanotherbozo]

I have a 1k gavita de at 36" and a 1k blockbuster with glass at 24" and the gavita covers more area and is far brighter than the blockbuster.
The plants grow healthier, taller and stack more nodes being further away from the gavita.
I always have to clean my glass hoods. Its ridiculous how dirty they get!
I also have a blockbuster without the glass with an old 600 and it seems just as bright as my 1K with new hortilux under the glass.

...so i guess you agree that a layer of glass between your bulb and your plants is a bad idea? ...not clear on what you're sayin'.

peace, bozo

 

[Coconutz]

Ya... glass sucks!
Im done with it!

 

[flat9]

Interestingly, see this graph:

In theory 10 mm of fused silica glass has rather good transmission properties (seems about 93% of light gets through) in the region we care about (300 - 700 nm). Note that the cool tube I was using was just standard glass (which contains a bunch of other stuff which absorbs light), and not pure fused silica. It was also a bit thinner than 10 mm. So I think if you used the right material, you should be able to get a cool tube with maybe 95% of the light passing through.

Basically that's like saying you lose 30 watts (maybe about 10 PAR watts) on a 600 watt bulb. If anyone actually manufactured a cool tube like this, I think they would probably be pretty helpful....

 

[DHF]

Borosilicate glass may be the lesser of all evils , but still....ANY loss is hurtin bottomline returns....bet on it....now....

I`ve heard good things bout Gavita`s and E-Pappilons(sp) , but ALL hoods with glass be it horizontals OR vertical "fooltubes" suck cawk with lumenloss waaaay more than the hydro whore manufacturers want yas to know....and finally....

Bare bulbs rule , and ALL else drool.....guaranteed....anyways....Folks will ALWAYS experiment for their OWN proof regardless of old farts like me screamin and preachin so caveat emptor.....let the buyer beware.....

50 watts per sq ft of uninterrupted lumens will make yas happy guaranteed...

Peace...DHF........

 

[Dropped Cat]

Cooltubes are a plus for my small grow. I use a 150w vert
in a 18" x 20" footprint. Sealed Cooltube vented by itself allows me
to vent for my plants as the need it.

I push 120 grams each grow, no worries.

Cooltubes have their place and should be used knowing
the trade off. Putting some glass in front of a light reduces
lumens, yup.

 

[flat9]

Borosilicate glass may be the lesser of all evils , but still....ANY loss is hurtin bottomline returns....bet on it....now....

I`ve heard good things bout Gavita`s and E-Pappilons(sp) , but ALL hoods with glass be it horizontals OR vertical "fooltubes" suck cawk with lumenloss waaaay more than the hydro whore manufacturers want yas to know....and finally....

Bare bulbs rule , and ALL else drool.....guaranteed....anyways....Folks will ALWAYS experiment for their OWN proof regardless of old farts like me screamin and preachin so caveat emptor.....let the buyer beware.....

50 watts per sq ft of uninterrupted lumens will make yas happy guaranteed...

Peace...DHF........

That depends on the scale of your grow, though, and your heating issues, right? Also, note that the chart I showed above wasn't from a hydro manufacturer; it was from the chemical physics department at Cambridge.

For instance, let's say for argument's sake you can run a 5 x 5 x 8 room w/ a 1000 watt bulb 10 degrees cooler with a cool tube than without w/ a 300 cfm fan, but could equate the temps with 600 cfms. Well, it probably costs you about an extra 100 watts to do so, whereas you might have only lost 50 watts of light, in which case you're being less efficient by using a higher cfm fan. Moving along in the thought experiment, how does this scale with room size?

No doubt what you recommend works, and works well! And thanks as always for dropping knowledge on here -- I've definitely learned a ton from reading your posts DHF. But what I'm very curious about is the following:

-- Is there a better way to make these tubes, sourcing such materials, in a DIY fashion (or even market such tubes)?
-- What's the equation/break-even point in terms of watts and room size at which it makes sense to just use higher CFM fans, ACs, etc. over such tubes? Does such a point even exist (i.e., is it ALWAYS better to use bare bulbs no matter what?

It feels to me that the grow fixture manufacturers haven't necessarily though all of this through (admittedly, they have a financial incentive at times not to). I think there's gotta be a way to be more precise on what types of grows to use these for, if at all. Not everyone will be able to rock huge grows w/ 10 x 10 rooms, etc. (though we all wish we could!).

I guess I'm a bit of a math nerd and want to develop an equation for growing weed.

 

[BredForMeds]

been pulling my glass out for Winters.. and really been seeing a huge difference in yield.. my winter grows yield an extra Pound . .. im stuck at .75 grams per watt... and hoping that adding a vertical barebulb MH in the Middle of my HPS will help.. but I don't know man.. if this doesn't help.. im going to have to go STADIUM VERT.. and that's going to be lots of work.

 

[DHF]

That depends on the scale of your grow, though, and your heating issues, right? Also, note that the chart I showed above wasn't from a hydro manufacturer; it was from the chemical physics department at Cambridge.

For instance, let's say for argument's sake you can run a 5 x 5 x 8 room w/ a 1000 watt bulb 10 degrees cooler with a cool tube than without w/ a 300 cfm fan, but could equate the temps with 600 cfms. Well, it probably costs you about an extra 100 watts to do so, whereas you might have only lost 50 watts of light, in which case you're being less efficient by using a higher cfm fan. Moving along in the thought experiment, how does this scale with room size?

No doubt what you recommend works, and works well! And thanks as always for dropping knowledge on here -- I've definitely learned a ton from reading your posts DHF. But what I'm very curious about is the following:

-- Is there a better way to make these tubes, sourcing such materials, in a DIY fashion (or even market such tubes)?
-- What's the equation/break-even point in terms of watts and room size at which it makes sense to just use higher CFM fans, ACs, etc. over such tubes? Does such a point even exist (i.e., is it ALWAYS better to use bare bulbs no matter what?

It feels to me that the grow fixture manufacturers haven't necessarily though all of this through (admittedly, they have a financial incentive at times not to). I think there's gotta be a way to be more precise on what types of grows to use these for, if at all. Not everyone will be able to rock huge grows w/ 10 x 10 rooms, etc. (though we all wish we could!).

I guess I'm a bit of a math nerd and want to develop an equation for growing weed.

Waaaay back when , I got 3 cooltubes free as a promotional with a big order from mdhydro.com , and they were bein hyped pretty good at the time cuz they`d just come out , so I said fuck it I`ll try em........

In my ebb and flow bucket rooms the ceilings were angled like a "hip roof" to blast lumens back down and all around the 35 buckets cuz there`s very little output directly under the bulbs , thus the "angular" setups for optimum penetration.....well...

I pulled a room , and before re-planting I hung the cootubes inline with insulated solid duct in the room , thru the lights , and out...btw....When cooltubes came out they had bout a 1/3 covered in metal for reflectivity back down to the plants.....yeah right......

Come harvey I`d lost 40 fukin % of my regular pulls from my bare bulbs , so I yanked them bitches out and used em for target practice at the farm , and that was the 1 and ONLY time I ever tried reflected light to grow dope with.....that said....

I pulled 5 lbs EVERY run in the bare bulb rooms consistently , and that 1 room took waaay more lollipoppin and tendin to only end up with right at 3 lbs with all things being equal in each room , and I was beside myself.......so....

Flat....1000 watter in a 5x5 `s still only 40 watts per sq ft and then you`re gonna wrap the bulb in glass ?......now don`t get me wrong guys....

If the ONLY wayta control environment in your grow area calls for air cooled reflectors be it horizontal or vertical , then by all means use whats necessary to dial your setup , but....

I ran the FUCK outta 3-600`s stacked in 6x6 inside dimension fliprooms to the tune of 8 rooms at 4 separate locations 24/7/365 many yrs with major air exchange twice per minute dialed to the tits , but with all the conditioned environment being produced in lungrooms to get pumped into and sucked out of each room constantly , so...

That`s why I`ve always preached bare bulbs in ANY situation big or small , but runs under yer belt and dialing the same room over and over takes time so go with whatchas know till yas get comfortable with runnin bare bulbs.....and finally...

I`m not sure there`s any glass that`ll come close to lumen output of bare bulbs blastin sideways 360 degrees around the room hittin walls and ceilings covered in reflectix/prodex/orca of your choice and budget FTW , so alas Flat I just can`t climb on board the bandwagon for ANY use of ANY type fukin reflector period......but...

To each his own , and far be it from me to discourage trial and error in the quest for knowledge , experience , and dialage , so carry on and keep us updated.....

Peace....DHF..........

 

[BlueGrassToker]

A tube can be a great tool to do things one might not be able to achieve without it.

I have a 2ft x 2ft DS60 tent that I have a vertical 400CMH. Now, I could run a bare bulb horz overhead of a scrog and be fine. However I could never run any bare 400watt bulb vertically amongst the foliage in the smallest tent made. Not without major fail.
Using a tube I can have the 400 right in the middle of some nicely stretched plants...and Much closer to them than I could ever get them with a bare bulb. Those into math and all...try researching the difference in loss of useable light through glass vs the loss seen by having a plant further away. I think you'll find that the fact that you can get your plants within mere inches of the glowing chemicals by far overrides any losses of light through the tube. -be it pyrex or cheap mexican lead.

Yeah, a bare bulb scrog would work fine...but I guarantee I pull better numbers vertically. 1/2lb+ every 8-10wks easy. A bare bulb scrog aint gonna do that in a 24"x24" space.

 

[DHF]

A tube can be a great tool to do things one might not be able to achieve without it.

I have a 2ft x 2ft DS60 tent that I have a vertical 400CMH. Now, I could run a bare bulb horz overhead of a scrog and be fine. However I could never run any bare 400watt bulb vertically amongst the foliage in the smallest tent made. Not without major fail.
Using a tube I can have the 400 right in the middle of some nicely stretched plants...and Much closer to them than I could ever get them with a bare bulb. Those into math and all...try researching the difference in loss of useable light through glass vs the loss seen by having a plant further away. I think you'll find that the fact that you can get your plants within mere inches of the glowing chemicals by far overrides any losses of light through the tube. -be it pyrex or cheap mexican lead.

Yeah, a bare bulb scrog would work fine...but I guarantee I pull better numbers vertically. 1/2lb+ every 8-10wks easy. A bare bulb scrog aint gonna do that in a 24"x24" space.

I fully understand the laws of "diminishing return" from the further away from the light , and in such small surroundings with 100 watts per sq ft , you BEST have it covered or suffer the consequences......

All about controlling environment FIRST , the proper watts per sq ft follow right behind...anyways...Glad yas got yer lil tent dialed and hoonin where it produces enough dope to last yas till next Harvey...but.....

With ANY room big enough to utilize bare bulbs , guaranteed they squash the shit outta any reflector on the market , horizontal OR vertical....witnessed it first hand and have 1000`s of testimonies from folks I`ve brought into the light so to speak over the yrs....

Peace....DHF........

 

[Mister_D]

That depends on the scale of your grow, though, and your heating issues, right? Also, note that the chart I showed above wasn't from a hydro manufacturer; it was from the chemical physics department at Cambridge.

For instance, let's say for argument's sake you can run a 5 x 5 x 8 room w/ a 1000 watt bulb 10 degrees cooler with a cool tube than without w/ a 300 cfm fan, but could equate the temps with 600 cfms. Well, it probably costs you about an extra 100 watts to do so, whereas you might have only lost 50 watts of light, in which case you're being less efficient by using a higher cfm fan. Moving along in the thought experiment, how does this scale with room size?

No doubt what you recommend works, and works well! And thanks as always for dropping knowledge on here -- I've definitely learned a ton from reading your posts DHF. But what I'm very curious about is the following:

-- Is there a better way to make these tubes, sourcing such materials, in a DIY fashion (or even market such tubes)?
-- What's the equation/break-even point in terms of watts and room size at which it makes sense to just use higher CFM fans, ACs, etc. over such tubes? Does such a point even exist (i.e., is it ALWAYS better to use bare bulbs no matter what?

It feels to me that the grow fixture manufacturers haven't necessarily though all of this through (admittedly, they have a financial incentive at times not to). I think there's gotta be a way to be more precise on what types of grows to use these for, if at all. Not everyone will be able to rock huge grows w/ 10 x 10 rooms, etc. (though we all wish we could!).

I guess I'm a bit of a math nerd and want to develop an equation for growing weed.

What you failed to consider here is, the cost of running an extra 50-100 watts more cooling vs. the added value of the increase in yield. I guarantee the added yield of running bulbs with no glass (provided all other environmental factors can be keep in line), will more than pay for the added power cost. IF you find yourself unable to control temps, then yes an aircooled reflector is a better option. At what point either option is justified will be unique to each setup.

 

[flat9]

Thanks for the thoughts guys! Good point Mister_D about the value of increased yield, but not all are medical/commercial growers. The "cost" I was trying to optimize was efficiency, not profit.

Speaking of which, if profit is your motive, wouldn't it be better to go way beyond 50 watts per sq. foot? I'd imagine that once you have temps and RH under control, you're always best pumping up the watts to as much as our space will allow in terms of increasing profits.

 

[Dropped Cat]

Thanks for the thoughts guys! Good point Mister_D about the value of increased yield, but not all are medical/commercial growers. The "cost" I was trying to optimize was efficiency, not profit.

Speaking of which, if profit is your motive, wouldn't it be better to go way beyond 50 watts per sq. foot? I'd imagine that once you have temps and RH under control, you're always best pumping up the watts to as much as our space will allow in terms of increasing profits.

Much more than 50 watt per sq. foot, diminished returns.

More posts from others about this idea to follow.