Help me choose a light

[Magnus A]

Originally Posted by billc

T12's are about the same size/ bulk as T5HO, although the T5HO gives a heck of a lot more light.

Bill

Bill, I think you need to check the specifications on T12 compared to T5! T5 are way more compact and give much more light. You can also mount the T5 much closer as they are slender which make the reflectors much smaller in dimension.

/M

[billc]

The bulbs are certainly smaller(diameter wise) and the light given is a lot stronger with the T5's. I have a 4 foot 4 light T5 and it really doesn't take up any less room than the 2 2 bulb T12's mounted side by side that it replaced. I'm just saying on an 8 foot table, Naoki is right that he could still use the existing T12's next to the new T5.

Bill

[Magnus A]

Bill I agree that existing T12 could be used but I strongly disagree that T12 and T5 take up the same space.

Everything is up to the ramp design.
A T5-tube with a reflector take up 4 cm (1.6'') that is as wide as a T12 tube without a proper reflector! A good reflector is about 2.5-3 times wider than a tube and thereby you can fit 2 T5-tubes on the with of one T12!
My T5 ramp with 4 tubes and individual reflectors is 8'' wide... (and I can´t even buy a T12 ramp in Sweden as it is to outdated and inefficient)

[billc]

I guess we have different configurations in mind. What I would assume(and I could be totally off base) is in North America people using a 4 light setup are referring to something along these lines:
Hydrofarm FLP44UN 4FT 4 Lamp T5 Fluorescent Grow Light - Plantlighting Hydroponics

I just measured my 2 bulb T12's and with the cheapo reflector the width is 7 inches (15.24cm).

Bill

[Call_Me_Bob]

Originally Posted by billc

T12's can bloom phals and paphs. You do have to move them when they spike.
Bulbs going out all the time doesn't sound right. Are you getting them wet?
T12's are about the same size/ bulk as T5HO, although the T5HO gives a heck of a lot more light.

Bill

nobody said they cant. i have been growing under them for years.

the fixtures i have are just old so the bulbs go out quickly and the fixtures are starting to go out all together.

t5's are definitely smaller then t12s. and they are more powerful which means that i can have the light farther away from the plants. which means i can water and take care of the pants easier

Originally Posted by billc

The bulbs are certainly smaller(diameter wise) and the light given is a lot stronger with the T5's. I have a 4 foot 4 light T5 and it really doesn't take up any less room than the 2 2 bulb T12's mounted side by side that it replaced. I'm just saying on an 8 foot table, Naoki is right that he could still use the existing T12's next to the new T5.

Bill

the fixture im getting will be about 15" wide. the two 2 bulb t12 fixtures i have mounted side by side take up about 20" of space. not much of a difference there. but the t5 fixture will be thinner then the t12 fixtures and way more efficient. there nothing saying i can't use the t12s. but im saying i dont want to. because they are bulkier and uglier, less efficient, have to be too low for my liking, and the ones i have are starting to break. this setup is in my room, so it needs look decent.

dont forget that there will be two windows behind the stand that will give me light. so the extra dome lamps would just be in case i need extra. and the dome lamps would be able to be used without taking up 4 feet of space.

Originally Posted by Magnus A

Bill I agree that existing T12 could be used but I strongly disagree that T12 and T5 take up the same space.

Everything is up to the ramp design.
A T5-tube with a reflector take up 4 cm (1.6'') that is as wide as a T12 tube without a proper reflector! A good reflector is about 2.5-3 times wider than a tube and thereby you can fit 2 T5-tubes on the with of one T12!
My T5 ramp with 4 tubes and individual reflectors is 8'' wide... (and I can´t even buy a T12 ramp in Sweden as it is to outdated and inefficient)

Originally Posted by billc

I guess we have different configurations in mind. What I would assume(and I could be totally off base) is in North America people using a 4 light setup are referring to something along these lines:
Hydrofarm FLP44UN 4FT 4 Lamp T5 Fluorescent Grow Light - Plantlighting Hydroponics

I just measured my 2 bulb T12's and with the cheapo reflector the width is 7 inches (15.24cm).

Bill

just something else to mention. the reflectors on the t5 fixture ill be getting are way more efficient then the reflectors that the t12s i have are. the t12s have reflectors that very inefficiency, more like a housing than reflectors

[Magnus A]

Originally Posted by billc

I guess we have different configurations in mind. What I would assume(and I could be totally off base) is in North America people using a 4 light setup are referring to something along these lines:
Hydrofarm FLP44UN 4FT 4 Lamp T5 Fluorescent Grow Light - Plantlighting Hydroponics

I just measured my 2 bulb T12's and with the cheapo reflector the width is 7 inches (15.24cm).

Bill

Not really, I have the same configuration but the tubes are mounted with individual reflectors very closed to maximize the light. My 4 T5 with reflextors span 20 cm (8'') across.
My light setup:


You see the individual T5 tubes under the reflectors on both sides. The gray metal case is 17.5 cm or 7''.

[naoki]

A couple more addition to Bill's comment.

It is good to worry about the efficiency (efficacy) because you'll be paying hundreds of dollars for electricity over years. I think some shop light accept both T8 and T12. If yours can take T8 (and if the ballast is decent), the efficiency of T8 is nearly same as T5HO (the quality/type of ballast does influence the actual efficiency, though). Fluorescent-lamp formats - Wikipedia, the free encyclopedia

If you are concerned about the total cost (fixture + electricity + annual light bulb change), T8 is probably better than T5HO (for a given amount of light) because the T5HO bulbs are still more expensive.

If you are comparing T12 and CFL, the efficiency isn't so different. For example, 32W CFL is around 2000 lumen (62.5lm/W). 40W T8 is 2000-3000lumen (50-75lm/W). If you want to have concentrated light, CFL might be better.

[Call_Me_Bob]

Originally Posted by naoki

A couple more addition to Bill's comment.

It is good to worry about the efficiency (efficacy) because you'll be paying hundreds of dollars for electricity over years. I think some shop light accept both T8 and T12. If yours can take T8 (and if the ballast is decent), the efficiency of T8 is nearly same as T5HO (the quality/type of ballast does influence the actual efficiency, though). Fluorescent-lamp formats - Wikipedia, the free encyclopedia

If you are concerned about the total cost (fixture + electricity + annual light bulb change), T8 is probably better than T5HO (for a given amount of light) because the T5HO bulbs are still more expensive.

If you are comparing T12 and CFL, the efficiency isn't so different. For example, 32W CFL is around 2000 lumen (62.5lm/W). 40W T8 is 2000-3000lumen (50-75lm/W). If you want to have concentrated light, CFL might be better.

im comparing efficiency of t12s and t5s. i think most t12 fixtures can take t8 bulbs. t8s are more efficient then t12s. true, t8's and t5's are not that different in terms of efficiency and output, but t5s take up less space, therefore they are more efficient in terms of Output to Space Taken

however, what ive been referring to this whole time are T5 High Output (T5HO) lights. The HO lights have an output that is almost twice that of a normal T5 or a T8

i found this


309ecm03fig1 by orchidman10, on Flickr

[Magnus A]

I have never considered the "normal" T5, therefore I did not recognize the statement that T5 and T8 had the same efficiency above.

I can by 54w T5HO fullspectrum 6500K in Sweden for about 7 dollar each. I consider that neglectible compared to other costs associated with our hobby...

[naoki]

[QUOTE=Call_Me_Bob;522826]true, t8's and t5's are not that different in terms of efficiency and output, but t5s take up less space, therefore they are more efficient in terms of Output to Space Taken
[\QUOTE]

That's right. You should note that the temperature influence the efficiency differently, though. You are also right about the space-efficiency. As you mentioned, 2 bulbs of T8 has similar output as 1 bulb of T5HO. If you need to put lots of lights for high light orchids, then T5HO is better.

The other advantage of T5/T5HO is that the reflector can be more efficient.