# What type of T5 bulbs do you use?



## silence882 (Feb 6, 2014)

Hi all,

I have had a T5 fixture over my orchids for about 10 months now. It seems to be working alright, but I'm thinking about switching the bulbs. I am using the bulbs that came which the fixture which are Agrobrite 54W High Output with a color temp of 6400K.

Has anyone tried out other bulbs that have worked well or not so well?

--Stephen


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## papheteer (Feb 6, 2014)

I have tried a combo of 3000K and 6500K before but I find all-6500K works best. Also I have reduced light intensity from about 900-1000FC to about 400-600FC. Plants are looking better.


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## consettbay2003 (Feb 7, 2014)

What is the length of the fixture and how many bulbs? What is the distance to the top of the leaves?


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## Chicago Chad (Feb 7, 2014)

I use the Plantmax 2 bulb 2FT T5 with 6400K bulbs. I have used 3000K but I do not think they are necessary or provide any noticeable benefits. They are positioned at a distance of 14 to 1" depending on the plant. I think 12" or more is appropriate for most Paphs, some like a little more distance. I do have some troubling slightly toasting certain species like sangii, appletonianum, gigantifolium and a few others, but reducing fertilizer levels seemed to help quite a bit. I have found that Brachy's and Parvi's fair much better than MF's or other sections with these conditions.


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## TyroneGenade (Feb 7, 2014)

This thread suggests Osram Flora: http://www.slippertalk.com/forum/showthread.php?t=32896 but I would still suggest LEDs such as what Ray is selling: http://firstrays.com/cart/Plant-Lights/LED-Vivarium-Grow-Lamp The emmision spectrum very closely matches the absorption spectrum of plants which should translate into more bang-for-your-buck.

That said, if you are more interested in saving money then 6400 (daylight) K tube should be OK.


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## Chicago Chad (Feb 7, 2014)

I have very good results with Rays LEDs over my paph seedlings as well. (distance of 12") Many of them are in bud for the first time.


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## AdamD (Feb 8, 2014)

I recently ran in to David Bird at the OSOGSL show and sale. He grows in a cave near Kansas City using many HPS lights (rather inventive!). He told me he is in the process of installing many LEDs all over to supplement blue spectrum. He said he would switch over to all LED if only he didn't have to supplement an outside heat source. He was in fact the only grower at the show to receive AOS awards, one on a dendrobium and the other on a Peruflora's Circla Alca.


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## silence882 (Feb 10, 2014)

Thanks for all the advice!

I am currently using 2 4-foot bulbs (of a 4-bulb setup) 18" from the top of the leaves. I may add a third bulb in a while. I had an HID set-up that over-lit the plants and they are still recovering.

I would definitely try the Osram Fluora bulbs if they were available in T5, but they've only got them in T8 as far as I can find.

I guess I will stick with 2 6400K bulbs. Perhaps I will see if I can find a supplemental LED.

--Stephen


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## polyantha (Feb 12, 2014)

silence882 said:


> I would definitely try the Osram Fluora bulbs if they were available in T5, but they've only got them in T8 as far as I can find.
> 
> --Stephen



There are alternatives:

KZ Fiji purple
Aqualine plant grow
ATI purple plus

I think that the aqualine bulbs will be the best because they emit red light at a better wave length around 660nm. I have ordered four bulbs and am currently testing...I will share the results in the other thread.


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## silence882 (Feb 12, 2014)

Excellent! I look forward to seeing your results.

They seem like pretty pricy bulbs, so it will be nice to see some actual data before deciding on whether or not they're worth it.

--Stephen



polyantha said:


> There are alternatives:
> 
> KZ Fiji purple
> Aqualine plant grow
> ...


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## silence882 (Feb 20, 2014)

I decided to try out an Aqualine Plant Grow bulb and received this from UPS:







Inside were 2 pieces of a formerly useful item (I only took one out to snap pics so I could get a replacement):





Usually UPS is pretty good, but this bulb was very well packed and they still managed to break it. They must have really bent the hell out of the box.

I bought it from Petco and they should be sending me a replacement so this is more of an inconvenience than anything else.

--Stephen


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## polyantha (Feb 20, 2014)

Oh nooo! Sorry to hear that. These bulbs will be pretty good I think. The results look promising so far.


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## mrhappyrotter (Feb 22, 2014)

This may or may not be a stupid post, but I'm going to go with it anyway.

What benefit do T5's provide? I've switched over to T8s in the past few years, and what I'm finding is that I have to grow the plants much further away from the bulbs than did with T12s to begin with. In some cases, I've removed bulbs from the fixtures to reduce the amount of light because both my paphs and my phrags were showing signs of getting too much light.


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## jeremyinsf (Feb 22, 2014)

T5 is more 'efficient' - which, in some cases, creates a mixed bag. Perhaps read this:

http://www.lightingsolutions.ca/news/t8-vs-t5-fluorescent.html


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## naoki (Feb 23, 2014)

jeremyinsf said:


> T5 is more 'efficient' - which, in some cases, creates a mixed bag. Perhaps read this:
> 
> http://www.lightingsolutions.ca/news/t8-vs-t5-fluorescent.html



I think they are talking about T5 normal output, not T5HO, which we usually use. With efficiency, the temperature influence the advantage of T5HO vs T8. But for the temperature good for orchids, I thought T8 was more efficient than T5HO. T5 normal output is most efficient, though.


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## jeremyinsf (Feb 23, 2014)

naoki said:


> I think they are talking about T5 normal output, not T5HO, which we usually use. With efficiency, the temperature influence the advantage of T5HO vs T8. But for the temperature good for orchids, I thought T8 was more efficient than T5HO. T5 normal output is most efficient, though.



I was probably being too general in using that term.

This page has more stuff:
http://www.lightingtaxdeduction.org/technologies/t5.html

I'd still use the same term, perhaps just not here with us technical folk


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## consettbay2003 (Feb 25, 2014)

I am in the process of switching from T5HO 6500K to T5HO 4000k. I've been using the former for over a year and I have a feeling it is favouring the 
vegetative growth excessively. Most of the information suggesting 6500K is
not directed at orchid growers - Please don't ask me to elaborate.


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## fibre (Feb 28, 2014)

I use the T5HO 6500K for about one year too. The flowering of my Paphs is quite well. I don't see less flowers now. My plants got natural light on my windowsills before.


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## silence882 (Mar 27, 2014)

Quick Update: I've been using one Aquiline bulb along with one 6500K bulb for about a month and my plants look greener and more robust. I am now a believer, despite the price.

I now do not trust my agrobrite 6500K bulbs. I think I will switch to a 3-bulb setup 24" from the plants with the Aquiline bulb, a GE 6500K bulb, and a GE 3000K bulb.

Another question: How long do you go before changing bulbs?


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## likespaphs (Mar 27, 2014)

six months to a year is the standard boilerplate


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## naoki (Mar 27, 2014)

According to a couple web pages (google T5HO lumen maintenance), T5 (and probably T5HO) seems to have a longer life than T8.

http://ecmweb.com/archive/t5-fluorescent-lamp-coming-strong












With 13h/day, it is 4745h/year. With these figures, they are assuming continuous lighting. In reality where we turn them on and off once a day, the light bulbs wear faster. Still I think I can go for 2-3 years (actually I would probably move to all LED).

There are also the issues of color shift in addition to the intensity decay. But I'm not sure how it will influence the plant photosynthesis. Isn't it possible that the spectrum becomes better when warmer bulb shift toward more blue output? But I don't think we can find the PAR (instead of lumen) maintenance curve published anywhere.


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## TyroneGenade (Mar 27, 2014)

From an aquarium perspective I have had a look into lamp lifespan and like Naoki, I haven't found the "6 month" rule to be supported by the data...

A friend and I have been comparing lamps for several years now based on plant physiology and lamp physics data and it seems that warm whites and daylights are about half as efficient compared to "plant gro" lamps like Gro-lux and Fluora-Glo when it comes to useable photons... I had originally rejected this idea as I had grown plants just fine under daylight and cool whites but the actual data speaks against this when the plant growing conditions are ideal.

So, with that said, if you are seeing such a big improvement with the plant-grow lamps then its a sign that you have otherwise near ideal plant growing conditions. We look forward to seeing photos of your flowers.

Incidentally, we find almost no T5 advantage over T8 tubes (http://www.apsa.co.za/board/index.php?topic=4454.0 ) as they both employ the same physics and chemistry. Where T5s have a big advantage is in their small size (relative to T8s) that enable you you squeeze more watts of light into the same space and that their narrowness means that less light is lost when you employ a reflector. A good deal of light gets lost in a reflector when you use a thick T8 or T12 tube. Geometry matters (http://www.apsa.co.za/board/index.php?topic=4379.msg41393#msg41393 ).

I still vote for LEDs over tubes. They are leaps and bounds way more efficient than tubes. Watt for watt, you may need only a 5th of T8 watts if you run LEDs instead.


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## naoki (Mar 27, 2014)

Great info, Tyrone! I have to study the german link you posted there (there are so much interesting info about plants in German..., I should have studied German harder when I was an undergrad).

The calculation of efficiency posted by Greystoke in the first link is interesting. I didn't know that it is so high for fluorescent light (about 27.5% of electric energy is converted to visible light energy). I think that with modern white LED (e.g. Cree CXA-3070) and 90% efficiency constant current driver, you get about 27-36% (higher efficiency with lower driving current). But CXA-3070 is one of the top end (for commonly available LEDs with reasonable cost) in terms of efficiency at this moment. I finished drilling/tapping the heatsink, so I hope I have some time to test out my CXA-3070 rig this weekend!

You are right that the LED is directional (an advantage over T8), but "LED watt = 5th of T8 watt" seems a bit too extreme, doesn't it? With white ones, I have thought that you can go by reducing 10-20% of watt to get similar PAR (i.e. 25-29W LED instead of 32W T8).


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## TyroneGenade (Mar 27, 2014)

naoki said:


> You are right that the LED is directional (an advantage over T8), but "LED watt = 5th of T8 watt" seems a bit too extreme, doesn't it? With white ones, I have thought that you can go by reducing 10-20% of watt to get similar PAR (i.e. 25-29W LED instead of 32W T8).



At first we were predicting somewhere between 2 and 3 times more potent but then I found this: http://www.advancedaquarist.com/2013/3/review and http://www.buildmyled.com/12000k-reef-spectrum/ (see produce specs lower down). That 48 inch LED is about 100 W/m2 and is getting about 110 PPFD at about 17 inches water depth. You would need about 300 W/m2 of T8/T5 lighting to do that and my math is VERY generous with respect to reflector efficiency and how much light actually enters the water (my model is buried in that first APSA thread). Somewhere around 3x more effective looks like the best guess (I struggle to recall my reasoning for 5x... maybe it was a typo?).

I think we could safely cut out power consumption by a third if we switched to LEDs for growing.

PS. most of the above only really applies to fishtanks. Even with a really good reflector only about 75% of the light is focused onto where it is supposed to go so LEDs (which focus light downward) are at least 1.33x as efficient as T5/8 lamps. If you are not using reflectors then only about 25% of the light is reaching your plants, in which case LEDs are 4x as efficient. Assuming you want to mimic shade (20000 lux) or overcast light (2000 lux), this would amount to between somewhere between 190--250 W/m2 or 19--25 W/m2 of LED light if you chose the correct beam angle to have all the light focused on the plants. The plants directly under the lights would have 2.5x the lux as those on the periphery so you can distribute the plants under the lights based on what you think they really need. For comparison, you would need 433 and 43 W/m2 with T5/T8 tubes (if you have a great reflector!) so theoretically, LEDs are 2.3x more efficient for our purposes. Where the Lux-based math breaks down is that plant-gro lamps typically have a lot less lux (but still pack a big photosynthetic punch). Typically, they have about half as much... so it is better work on the wattage than the lux. You need half the wattage of plant-gro lamps per watt of cool white/daylight lamp.


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## silence882 (Mar 29, 2014)

Thanks for all the info!

I think I'll try this set for a year and see how the plants do. If they still look good I'll wait until 2 years have passed to replace the bulbs.

I had another bad experience with only using one type of bulb many years ago. I think I am now a believer in using at least 2 types in each fixture.

--Stephen


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## silence882 (Apr 3, 2014)

The new GE bulbs arrived! I now have quite an array in my fixture.

From left to right: GE Starcoat 6500K, Aquamedic Aquiline, GE Starcoat 3000K




--Stephen


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## naoki (Apr 10, 2014)

Stephen, they look quite different in photos (human eyes seem to minimize the difference).

Tyrone, here is some data comparing the efficiency between LED vs florescent light:
http://cpl.usu.edu/files/publications/factsheet/pub__7199661.pdf
Table 3 Photon efficiency column. Super-high-end LED can be 2x more efficient, but most of LED (consumer-grade high-end) is only 19% more efficient than T8. I believe that efficiency of T5HO is similar (or slightly lower than) T8.


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## polyantha (Apr 11, 2014)

naoki said:


> Stephen, they look quite different in photos (human eyes seem to minimize the difference).



I noticed the same. My fixture with daylight and blue light was extremely white and blue on photo and even on the camera screen.


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## TyroneGenade (Apr 11, 2014)

Thanks for the data Naoki. But, just to be clear, the principal advantage from LEDs is the optics that produces a narrow beam of light. Even with a good reflector (most reflectors are not good as the tubes aren't placed deep enough into them) at least 25% of the light from a tube is wasted, and then the rest spreads out and grows "dilute" very quickly. While LEDs are only 19% more efficient at turning electricity into light, the optics makes them 1.3--2x better at actually getting the light to the plants.


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## Ray (Apr 11, 2014)

TyroneGenade said:


> From an aquarium perspective I have had a look into lamp lifespan and like Naoki, I haven't found the "6 month" rule to be supported by the data...



The folks at Hydrofarm tell me that one year is probably the safest/most economical point, while still ensuring decent lighting. When I have run a T5HO for 12-14 hours per day for a year, then replace it with a new one, I DO notice a difference in the brightness.

Shifting gears a bit - I now carry the Philips Green Power LED lamps (so far I only stock the White/Deep Red Flowering bulbs that screw into an incandescent socket), and am thinking about buying a couple of the Deep Red/Blue production modules (35W, 120 mm length) for my own use. They normally retail for as much as $240 each, but if I buy a case of 6, I can get them for about $150. Anyone want to jump in on that case?


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## Linus_Cello (Apr 11, 2014)

Ray said:


> The folks at Hydrofarm tell me that one year is probably the safest/most economical point, while still ensuring decent lighting. When I have run a T5HO for 12-14 hours per day for a year, then replace it with a new one, I DO notice a difference in the brightness.
> 
> Shifting gears a bit - I now carry the Philips Green Power LED lamps (so far I only stock the White/Deep Red Flowering bulbs that screw into an incandescent socket), and am thinking about buying a couple of the Deep Red/Blue production modules (35W, 120 mm length) for my own use. They normally retail for as much as $240 each, but if I buy a case of 6, I can get them for about $150. Anyone want to jump in on that case?



What does this "screw/insert" in to? The link mentioned "conventional flourescent." So like a T12?


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## Ray (Apr 11, 2014)

No, the ones I have in stock screw into a standard incandescent, "Edison Base" socket:





The "Production Modules" I'm thinking about are linear, stand alone lamps. Here's a video on someone experimenting with them for lettuce growing:
http://www.youtube.com/watch?v=u8-FKHAVsnA&list=UUkhj6cskGZ3fOU0uGyoqnoA&feature=share


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## naoki (Apr 11, 2014)

TyroneGenade said:


> Thanks for the data Naoki. But, just to be clear, the principal advantage from LEDs is the optics that produces a narrow beam of light. Even with a good reflector (most reflectors are not good as the tubes aren't placed deep enough into them) at least 25% of the light from a tube is wasted, and then the rest spreads out and grows "dilute" very quickly. While LEDs are only 19% more efficient at turning electricity into light, the optics makes them 1.3--2x better at actually getting the light to the plants.



Tyrone, take a look at the Methods section. The efficiency they measured is at the fixture level, so it is not comparing just the diodes. The data incorporate the efficiency of reflectors/lens and ballasts/controllers/drivers. They didn't mention a specific model of florescent fixture or bulb, though.

Ray, that's cool you are carrying these Philips GreenPower LED. They seem to have really high efficiency (if the numbers in the specification is correct). For the linear 4' models, the photon efficiencies are 1.43 and 1.67 micro-mol/J for Red/Blue and White/Red, respectively. These numbers are comparable to the best LED/HPS from the Utah study. It is interesting that White/Red has the higher efficiency than Red/Blue. The screw-in type is pretty efficient (1.22 micro mol/J), too. The linear one would be a nice replacement for florescent bulbs. They are surely pricey initially (even with your volume discount), but you probably save money over the cheaper LEDs in a long run. IP66 means that they are water-proof, right? They look like that they are fan-less, passive cooling, which is great for indoor, too.

I wonder what kind of White:Red ratio, philips GreenPower is using (I didn't see the info in Phillips site). I did make the public lab DIY spectrophotometer, and it works, but it wasn't good for my camera. Now I made a second version with a Cheerio box, which is much easier and seems to have a better resolution. I still need to figure out how to take photos with it. Maybe you can try it and measure the spectra.


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## Ray (Apr 11, 2014)

IP66 - the first 6 indicated dust proof, the second is the water intrusion level, 6 being protected against strong water jets.

They don't tell you the ratio, but here is the spectrum. The title at the top is reversed. That red peak reaches an absolute irradiance level of about 52 µW/cm2/nm, while the red on my little ones only reached 4. My blue peak is 13 compared to about 6 for the Philips lamp


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## junglejim (Apr 14, 2014)

Chicago Chad said:


> I have very good results with Rays LEDs over my paph seedlings as well. (distance of 12") Many of them are in bud for the first time.



Are you using the LED vivarium 13 watter, or the ones that replace the florescent tubes in light carts?


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