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lighting spectrum

  • Thread starter uphwiz
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uphwiz

jimmy
Im getting my first two bulb t5 HO fixture and have a glo HO t5 actinic blue spectrum bulb 54 watt, what should i put in with it , im thinking something in the red spec, say 5000 lumens w a 3000k spectrum 54 watt for the reds, or should i go with a multi spectrum bulb , i know there are several of these threads but . ive read several and am confused .
Help please
 
Im getting my first two bulb t5 HO fixture and have a glo HO t5 actinic blue spectrum bulb 54 watt, what should i put in with it , im thinking something in the red spec, say 5000 lumens w a 3000k spectrum 54 watt for the reds, or should i go with a multi spectrum bulb , i know there are several of these threads but . ive read several and am confused .

Hi Jim,

I'd go with a 6500K or 10,000K bulbs for such as small system. A 3000K spectrum bulb will be very yellow. With T5's a mixture of colored bulbs works well. A 3000K bulb is a great addition if you have 7 other bulbs of other colors. I am concerned that that you only have two tubes. Unless you have a very small space of illumination, 2 tubes is probably not going to be sufficient for most CP lighting needs. You have to think of T5s in terms of an array of many bulbs. T5s are good and flexible lighting but they require many bulbs to be optimally effective. If you are doing a typical grow shelf, you may need up to 10 tubes.

-Hermes.
 
one shelf of 18" x 46", and im using two t 12s now one ecoluxbulb 1900 lum don't see color temp on these(it does say for plant and aquarium and, one daylight bulb 2250 lum w/5000 color temp, ive had very good results whit these two bulbs, isnt the two t5 going to be stronger light with better results.
Iuse double this over my highland terr. and it is also doing well . so i was thinking about replacing one set at a time, and am looking for the best two bulbs i can use in this setup (IE) two bulb fixtures,added one at a time , or is this no better than the t12s im using now?
 
I use double this over my highland terr. and it is also doing well . so i was thinking about replacing one set at a time, and am looking for the best two bulbs i can use in this setup (IE) two bulb fixtures,added one at a time , or is this no better than the t12s im using now?

The mystique and tribal knowledge that surround T5s is somewhat unfortunate. Yes, it is true that T5s are more efficient than T12s but only at their proper operating temperature of 35 degrees Celsius, when it can be 45% more efficient. However, outside of this temperature range it is not significantly more efficient; most other fluorescent lamps are most efficient at roughly room temperature. Most aquarium hoods that use T5s are designed with this operating efficiency in mind.

There are two things to keep in mind with T5s. (1) They generally come with a highly efficient reflector, which concentrates the emitted light downward. Without this reflector, much of its efficiency is lost. (2) T5s are intentionally designed with a small form factor so you can pack them into a fixture.

If implemented correctly, T5s are fantastic lights. But they are more difficult to implement correctly than other lights. Most people tend to get sticker shock and undersize their lighting systems when it comes to T5s. But if properly scaled, T5s can give beautiful and effective light. I highly recommend their use; just implement them correctly.

-Hermes.
 
same question is the t5s im planning going to be better than the t12s im using now 54 watt t5 ,verses 32 watt t12
cant find my celsius to fahrenheit chart ,whats 35 degrees celsius in fahrenheit
 
same question is the t5s im planning going to be better than the t12s im using now 54 watt t5 ,verses 32 watt t12 cant find my celsius to fahrenheit chart ,whats 35 degrees celsius in fahrenheit

95 degrees F. Are T5s going to be better than T12s? Yes, but that is because T12s are woefully inadequate. Before anyone jumps down my throat, yes, I know lots of people use T12s with CPs successful. Nevertheless, T5s are not so much better that you can replace 2 T12s with 2 T5s and expect a huge improvement. But whether T5s give you the optimal lighting will depend upon how you implement them.

Using T5s requires a different kind of paradigm than using T12s. T5s are great but you need a lot of tubes to achieve adequate lighting; that's how they are designed.

-Hermes.
 
T5's aren't much better if you aren't getting a fixture with individual polished reflectors, which dramatically increase the efficiency and output of each bulb. I don't have exact numbers, but I know it's something crazy like double (or more) output with the polished reflectors. If you aren't getting a fixture with those, then I personally wouldn't bother with T5's at all - too hot, not worth the money (IMO), need more bulbs, etc, etc.
Be prepared to pay though, nice fixtures are not cheap.

Which one were you planning on getting? Do you have a link?
 
Herm,

IMHO the ambient temp issue is way overblown in our application. In the micro environment of the fixture this is not a problem when used for the typical grow rack. Now if they were in warehouse or an outside installation where they were not able to stay hot then yes.

Mine are in an non heated basement and the coldspot of my bulbs stay at the desired temp... I have personally checked with infrared. ( there is an old post ofmine about it)
Its just a non issue in my personal experience

Hi Jim,

If you are doing a typical grow shelf, you may need up to 10 tubes.

-Hermes.

I have to ask, but have you ever grown plants using T5's? Have you found the need for 10?
Going by my personal experience with them, I cant see the need for 10 tubes for a typical grow shelf... that just blows me away

FWIW, I ran all 5000k 85CRI up till very recently and had excellent results

Just my 2 cents

---------- Post added at 01:17 AM ---------- Previous post was at 01:13 AM ----------

T5's aren't much better if you aren't getting a fixture with individual polished reflectors, which dramatically increase the efficiency and output of each bulb. I don't have exact numbers, but I know it's something crazy like double (or more) output with the polished reflectors. If you aren't getting a fixture with those, then I personally wouldn't bother with T5's at all - too hot, not worth the money (IMO), need more bulbs, etc, etc.
Be prepared to pay though, nice fixtures are not cheap.

Which one were you planning on getting? Do you have a link?

This is very true.... it's 300% (Id have to dig though my data to get you a specific ref, but its well documented)
and the individual reflectors and short distance (relative) to the plant also reduces the benefits of mixing bulbs IMHO
again, by personal observation
 
This is very true.... it's 300% (Id have to dig though my data to get you a specific ref, but its well documented)

Thanks... I knew it was some insane percentage like that. lol
 
  • #10
I started with one T5HO 6500K, but noticed it lacked, mainly because i wasn't using a reflector. So I moved it up to two T5HO's and saw an improvement. When I added reflectors, it made all the difference in the world.

If T5's are better than T12's, I have no doubt in my mind. A lot of bulb is pointing in the wrong direction with T12's, no reflector can maximize a T12 as well as one for a T5 IMO. And T5's last much longer too(at near optimal efficiency).. How is this even debateable..
 
  • #11
Herm,
I have to ask, but have you ever grown plants using T5's? Have you found the need for 10?
Going by my personal experience with them, I cant see the need for 10 tubes for a typical grow shelf... that just blows me away

Nope, but I use 575W of MH's and 280W of CF's with excellent results. Have I found a need for 10 tubes? No, but again I don't use them. But if I was to duplicate my setup using T5s, I would need 10-12 tubes. But all this depends upon the size and depth of the growing rack. I illuminate 8 sq/ft at 24" from the light source. Would you say that 2 T5 tubes would be adequate for such a setup? Would 2 tubes even be adequate for a 6 sq/ft at 12" depth that is typical of normal grow racks? If you did, that would certainly blow me away.

This is why I said "you may need." Again, it all depends upon what his setup is as to what he will need. Yet, it appears that the tendency among adopters of T5s is to underscale not overscale their setups. You know, it would be very helpful if you carefully read my posts before commenting, Professor.

-Hermes.
 
  • #12
T5's aren't much better if you aren't getting a fixture with individual polished reflectors, which dramatically increase the efficiency and output of each bulb. I don't have exact numbers, but I know it's something crazy like double (or more) output with the polished reflectors. If you aren't getting a fixture with those, then I personally wouldn't bother with T5's at all - too hot, not worth the money (IMO), need more bulbs, etc, etc.
Be prepared to pay though, nice fixtures are not cheap.

Which one were you planning on getting? Do you have a link?
The unit im buying locally , they are ordering in with their stock order they do every other week ,
it does have reflectors but not polished, but neither do the t 12 fixtures.
the units im planing are 70.00 no shipping charges, each two bulb fixture, too much?
i will have to wire them my self may need a little advise on this aspect,but i am going to try one fixture. sorry i dont know the model # but will when it arrives it is High Output. thats about all i know about them.
 
  • #13
Nope, but I use 575W of MH's and 280W of CF's with excellent results. Have I found a need for 10 tubes? No, but again I don't use them. But if I was to duplicate my setup using T5s, I would need 10-12 tubes. But all this depends upon the size and depth of the growing rack. I illuminate 8 sq/ft at 24" from the light source. Would you say that 2 T5 tubes would be adequate for such a setup? Would 2 tubes even be adequate for a 6 sq/ft at 12" depth that is typical of normal grow racks? If you did, that would certainly blow me away.

This is why I said "you may need." Again, it all depends upon what his setup is as to what he will need. Yet, it appears that the tendency among adopters of T5s is to underscale not overscale their setups. You know, it would be very helpful if you carefully read my posts before commenting, Professor.

-Hermes.

Hermes, you said for a typical rack... and in the other thread of swords you came back and said that you were talking about a 400 watt Input fixture when they dont exist or if they do they are not typical either

I dont know of anyone who uses 10 tubes, much less 12... none

read your post carefully? LOL

How about you stop making wild statements based upon something you've read on the Internet Especially, when you dont have any actual experience with the item in question, Student

Im glad you use MH, nice lights. Ive personally grown plants using T12, T8, T5, MH and LEDs at one time or another, and I have 3 spectrometers that I use to "personally" measure their spectral preformance

Av

---------- Post added at 11:05 AM ---------- Previous post was at 10:37 AM ----------

Here is 8 sq. ft at 24" + distance

Typical rack, with 6 5000k 85CRI bulbs

sgh12_2009.jpg

sghA12_2009.jpg

p_agnata_csuf.jpg

ventricosa.jpg


Top shelf performance
ceph_typicals.jpg

motherwithtwins.jpg

redwistubaminor2008.jpg

wistuba_hybrid.jpg


(last image was taken outside to show the colors were indeed true)

You see Student, I know I'm no expert on lighting but my T5 comments are not based upon something that Ive read online or heard second hand. However, they are from actual experience and experimentation with the different lighting formats.

Av
 
  • #14
hey Av8tor, I'm a might confused now on T5s, They do not operate efficiently (better light than T12) unless I allow the lighting cabinet to get to 35*C?
I was planning to fill my area with wind so there wouldn't be any chance of letting the temps get that high if I decide to go with T5s and not the 8 fts.
I've just received 10x 35 CFM fans to put in the shelf part of my wall unit to expel heat. T5s can't actually run cool/room temp and be any good or rather their effectiveness is reduced to T12 levels anyway?
 
  • #15
No, not the cabinet really, the term ambient is a little misleading in this case... the cold spot of the bulb is what matters. Just looking at ambient temps is an over simplification.

The efficiency of all fluorescent lights drop once their cold spot temps drop below rated value. But this isn't really an issue, the center of my bulbs reach 160f (hottest spot for the T5) so they have no problem staying warm.

While it is true they need to run hotter then the other two common fluorescent formats.... their higher wattage and smaller surface area pretty takes care of this with room to spare. In fact as the T5 bulb ages its cold spot temps continue to rise. They require a end of life shutdown circuit in the ballast or this temp rise would continue to rise until the temp becomes critical and actually burns through the bulb itself.

Ron, has talked about running into that problem when using a certain brand of CFL some time ago...

Now if you were trying to install them outside during the winter or in a cold storage warehouse, then yes... you may have issues with a loss of efficiency.

Mine are in an unheated basement and I use fans... I have no issues, in fact most people complain about them running too hot. I don't know if I've ever heard a CP'er talk about their T5's running too cold

For freezer use, you can get short tubes that cover the cold spot region of the T5 to boost the temps back up

I have personally verified proper cold spot temps in my application

Is it possible, sure... is it likely in our application where we have multiple bulbs in mounted in highly efficient reflectors, (not only for the visible light but also the infrared spectrum), in my experience, no.

I would not point an air condition duct directly at them, but that's true for any format.

If the cold spot of the bulbs feels warm to you in normal operation, then you're just fine mate. If you are going to run ultrahighland temps with lots of airflow then separate the fixture with a thin layer of glass

Or even go with another option... but under that scenario you are going to have reduced efficiency issues with t8's, t12's and MH as well

Google "T5 cold spot" for more info

Av
 
  • #16
My intention was to run the fans across the lid glass (lexan) in an X shape (corner to corner and out the open back) with about 1-2" of gap between the glass and the lamp bottoms so there would be plenty of airflow across the sealed tops of the tanks. Plus the air/humidity duct putting cool air inside the tanks not on the lamps themselves.
 
  • #17
Then it should be a non issue mate ;)

Mine are not isolated in any way and I don't have any problems maintaining proper cold spot temps.

Av
 
  • #18
Hermes, you said for a typical rack... and in the other thread of swords you came back and said that you were talking about a 400 watt Input fixture when they dont exist or if they do they are not typical either

A true 400W input fixture might not exist, but even with a 20% energy overhead of MH ballasts we are only talking about 480W input. This is close enough. But that other post was claiming a double energy consumption over 480W of T12s. You should know that the energy consumption of either fixture should be approximately the same. And perhaps, I should have been more specific rather than use the word "typical." Either way, that was two posts ago and I had subsequently defined what kind of grow space I use, so the objection is no longer valid.

I dont know of anyone who uses 10 tubes, much less 12... none

Here's a commercial fixture that uses 10 tubes [http://reefbuilders.com/2009/09/30/reflektas-pm3-dimmable-t5-lighting-fixtures/]. Of course, I was thinking of more along the lines of 24" tubes and fixtures since the bulbs are often easier to find. And of course, Sfiligoi Stealth used to make a 12 tube fixture--I don't know if they still do. Here is someone who is using 12 tubes to grow orchids, mayres' post [http://www.orchidgeeks.com/forum/orchid-lighting/14598-what-t5-bulbs-are-best-for-phals.html] Of course, manufacturers love to waste money making fixtures that no one uses.

How about you stop making wild statements based upon something you've read on the Internet Especially, when you dont have any actual experience with the item in question, Student

You do not have to drink cyanide to know it is a bad idea. Hands-on experience is not the only way to learn something. If that was the case, why would anyone spend their hard earned money learning under your teaching when they can just go experience it for themselves? You can't be a very good teacher, Prof.

Nevertheless, I have used (and presently use) fluorescent lights to grow my plants. I have used T12s, T8s, and a variety of compact fluorescents. My suggestions are based upon my previous experience with these lamps combined with the manufacturer recommendations for T5s. I had also done my research on T5s since I almost purchased such a system; however, I was presented with a really good price on MH ballasts which is why I ended up going that direction instead of T5s.

Typical rack, with 6 5000k 85CRI bulbs

[gratuitous pictures snipped]

You see Student, I know I'm no expert on lighting but my T5 comments are not based upon something that Ive read online or heard second hand. However, they are from actual experience and experimentation with the different lighting formats.

Nevertheless, you are using a multiplicity of lamps--six of them by your own admission. So, in fact your counterexample is the exception that proves my case, which is that one needs many tubes, not just two.

Thanks...

-Hermes.
 
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  • #19
While your pictures are spectacular, they are also a straw man since they are not taken under T5s but T8 lamps, since "85CRI" bulbs are in fact T8 not T5. These pictures are not proof based upon any "actual experience" you have had regarding T5s.

-Hermes.

Dude...What do think T5 means? What does T8 mean?? The color rendering index doesn't define T5 or T8. 85 CRI can be produced by even metal halides. T5 bulbs are 5/8" in diameter, T8 are 1" diameter. Just because a specific phosphor composition of a T5 produces 85 CRI and not higher, it doesn't mean the bulb gets diminished to T8.
Those plants were grown under T5. Av has given a lot of demonstrations of his setup and based on that, I got a 4 tube T5 fixture with the same bulbs. It was Av's experience that convinced others and myself that T5s when used correctly can produce stunning results in horticulture.

here are some links that might be useful:

T5s : http://www.lrc.rpi.edu/programs/nlpip/lightingAnswers/lat5/pc1.asp
CRI: http://en.wikipedia.org/wiki/Color_rendering_index
 
  • #20
Dude... 85 CRI can be produced by even metal halides.

Good catch. Thanks for the correction.

Av has given a lot of demonstrations of his setup and based on that, I got a 4 tube T5 fixture with the same bulbs. It was Av's experience that convinced others and myself that T5s when used correctly can produce stunning results in horticulture.

This may be hard to comprehend but I agree with Av on T5 fixtures. They do produce stunning results in horticulture. I never said otherwise. Av and I agree more than we disagree when it comes right down to it. And while I am certainly no expert on lighting systems, I do think T5 fixtures are the best solution for those getting into high end lighting systems. My only problem with T5 fixtures is that people tend to underscale them, and thereby limit their potential effectiveness and versatility. That's really the only issue I have.

-Hermes.
 
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