Adding UVB spectrum to COBs - opinions on this setup?

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yosim

Well-Known Member
Hi,
spent last couple of days reading up on UVB addition to grows - some people seem to recommend and are getting good results

will agree that there doesnt seem to be any clear data or experiments (maybe there are but i havent seen them yet)

Im thinking of going with these UVB200 26w bulbs, possibly 2 of them http://www.exo-terra.com/download/sales_sheets/Sales_Sheet_Reptile_UVB_NA-EU.pdf

and putting them in this reflector http://www.exo-terra.com/en/products/compact_top.php

i can fit the small reflector in between the COB heatsinks on my fixture

UVB spec stated for that UVB200 is 40 microwatts/cm2 at 12 inches, 25 at 16 inches - is this too much or too little? I would probably buy 2 bulbs....would like to know if its worth the effort/money...

opinions?
thanks :)
 
researching

researching

Well-Known Member
Everything I have read and heard recommend uvb. I plan to add to my fixtures. I am looking at the flourescent tubes. Probably 2-3 for each 3x3 table. The only thing to be cautious about is not having them on when you are in the room due to potential damage to your eyes. I plan to run mine 15mins per hour. I havent settled on anything yet.

Another thing to consider is the areas of the world known for high uv rays. Those are typically places with higher altitude. Afghanistan and Pakistan are examples. Colorado also has high uv which is great if you grow outside.
 
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Shugglet

Well-Known Member
No way to say really. Do whatever floats your boat.

I'd be curious as to whether you'd be further ahead putting that extra wattage into regular light vs uvb.
 
OneHitDone

OneHitDone

Well-Known Member
Do cob's really need UVB supplementation? I was under the impression it is "Full Spectrum" and provides everything plants need
 
R

rhygin77

Member
Airwalker16 said:
No. Use these. They're the only bulb worth using. But they're SO intense you only run them maybe 15 min of the middle 4 hours of flower. That's it. This is the 4' but they also sell a 2'.

http://www.htgsupply.com/products/agromax-pure-uv-t5-bulb-4-foot
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Is it better than these:

http://www.ushio.com/files/specifications/low-pressure-mercury-arc-blacklight.pdf

Looks like it could be higher output (they don't give it as a factor of distance, so some math would be needed to make sure), unless there's something in the spec sheet that I'm missing. Not being snarky at all; I've just also been searching for the best options (and hadn't seen the one you linked).
 
Airwalker16

Airwalker16

Well-Known Member
rhygin77 said:
Is it better than these:

http://www.ushio.com/files/specifications/low-pressure-mercury-arc-blacklight.pdf

Looks like it could be higher output (they don't give it as a factor of distance, so some math would be needed to make sure), unless there's something in the spec sheet that I'm missing. Not being snarky at all; I've just also been searching for the best options (and hadn't seen the one you linked).
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Because the agromax bulbs throw out 76% UVB and 25% UVA. PURE.
@Tim Fox burned his back under just 15 minutes under one.
 
Y

yosim

Well-Known Member
rhygin77 said:
Is it better than these:

http://www.ushio.com/files/specifications/low-pressure-mercury-arc-blacklight.pdf

Looks like it could be higher output (they don't give it as a factor of distance, so some math would be needed to make sure), unless there's something in the spec sheet that I'm missing. Not being snarky at all; I've just also been searching for the best options (and hadn't seen the one you linked).
Click to expand...
datasheet doesnt seem to show microwatt/cm2 so hard to say
 
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rhygin77

Member
Thanks, I'll check it out. The ones I linked to are $33 (not really any difference, for me) and output almost 4 watts. I'll figure out how to covert that to microwatts as a function of distance.
 
Y

yosim

Well-Known Member
Airwalker16 said:
Because the agromax bulbs throw out 76% UVB and 25% UVA. PURE.
@Tim Fox burned his back under just 15 minutes under one.
Click to expand...
ouch!

so the agromax T5 Pure series lists "UV" output at 64 microwatts/cm2 at a distance of 4 Feet (on their website) - so will assume 48 microwatts/cm2 as this is 75% of 64 ?
i cant get these bulbs where i live anyway so that rules them out

Exo Terra UVB200 26 watt lists UVB output at 225 microwatts/cm2 at a distance of 4 inches (datasheet on website) - lists UVA output at 1350 microwatts/cm2

edit: feet not inches for agromax spec
 
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Airwalker16

Airwalker16

Well-Known Member
rhygin77 said:
Thanks, I'll check it out. The ones I linked to are $33 (not really any difference, for me) and output almost 4 watts. I'll figure out how to covert that to microwatts as a function of distance.
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They suggest having them at least 3-4' away
 
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Shugglet

Well-Known Member
rhygin77 said:
They don't provide UV-B. Whether it's needed, or even beneficial, is the subject of some debate. Do some reading and decide for yourself.
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The truth is there is hardly enough information available to even make a remotely educated decision even if you do your research.
 
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