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Lighting Comparison 2x T12 vs 4x T8

DrWurm

Californian in DC
So I got my 4 bulb fixture a few days ago, but the retailer forgot to include the lights and electrical cord. They shipped them out to me free of charge and they got here today. So I popped them in, wired it up, and hung the fixture from my new rack.

I ALSO got a DSLR camera a week ago, so I decided to take some comparison pictures.

These 2 side shots were taken in manual mode at f5.6 1/80s first is the t12 fixture.


These perspective shots show the effect on my whole room (which is a mess) at f4.0 1/80s


And finally, shooting the lights directly in aperture priority mode, (so the camera adjusts for shutter speed) both at f8.0
1/100......................................1/800


Suffice to say, these new lights bathe my room in a white glow. I'm thinking about getting some mylar, attaching it to black cloth and creating curtains (black on the outside, shiny inside) for this thing, so I can have a little darkness later in the day.

http://www.contractorlighting.com/h....html?osCsid=7476936ebb9f7e0ea8badffb7a2e7158

That's the one i picked up. The 95% reflector really makes a difference.
 
After just recently switching to T-8s as well, it was crazy to see that I can get more light from 4 T-8 bulbs than I can with 6 T-12s.
it looked almost like the plants under the T-12s were growing in the shade when i did a comparison with the blinding T-8s. The fixtures have single-handedly turned my sundew collection around. I will recommend to everyone that if you have some extra cash, hit up your local Wal-Mart and buy a fixture asap- (they're very cheap! :) ) Not only will they save you a lot of money for electricity, but they greatly improve/speed up plant growth.
 
Only $18 plus shipping? Quite a deal for a 4 lamp & plug - sounds very good!

How many lumens does a T-8 throw compared to a T-12? What is the actual difference between the two? Do T-8s come in daylight (6500K models) and still draw 40 watts each?

Would 4x T-8s in this "tall ceiling" reflector be equivalent (or better) of 2x 95W Power Compacts (3 ft long) for mounting over a 3ft tall landcsape vivarium that I have in it's planning stages?


Light Blocking:
Get to Home Depot or similar and find some Duct / Vent insulation, large reflective sheets of "foil" that are sturdy (not thin like tinfoil) and can be opened and closed over the life of your light garden. If you don't find that stuff then you can do my ghetto way of doing it: Lay out sheets of foil cut strips of duct tape and cover one side of the foil with it, when you're done these panels will be reflective inside, dull outside and last a very long time. I used this on my highland terrarium to keep from being blinded as the lights pop on in the morning. But I soon moved it to all my tanks. I don't have it on my anole's tank though the plants would probably benefit from it but It'd probly give the lizard cataracts... lol!
 
I think it's acually $110 w/ bulbs included and the plugs/cords are extra.

you can get 2 light 4-foot T-8 fixtures for around $10 bucks at your local Wally world and other places as well (bulbs not included). They are very affordable. Granted they don't sell a 4-bulb fixture there, but it gets the job done...

I buy the same brand (Ecolux) for both my T-12 and T-8 lights. The specs seem odd on the T-8 bulbs, since it says they actually have 700 lumens less compared to T-12 bulbs (3,500), but still produce WAY more light than T-12s. The T-8s have a slightly higher color temperature compared to T-12s, but not by much. maybe a "light expert" can explain this to me...
 
CPlantaholic is correct. The reason however, these lights are 110 dollars, and the lights at your local bargain store are 10 dollars, is mainly, i believe, because of the reflector.

Not all fluorescent fixtures are created equal. There's a reason these guys who sell 100+ dollar fixtures stay in business. High bay light fixtures have a specially designed reflector that reflects 95% of the light that hits it down. This means these fixtures emit a very tight cone of extremely intense light. When used with a grow rack, this ensures that the plants get much more light. Think about it, a normal light fixture without a reflector wastes about half the bulb's output lighting the top of the fixture.
 


I reoriented the light to compensate for plant height. Looks a little funny, but should yield good results.
 
T8 bulbs do produce less light overall. They look brighter because the surface area of the T8 bulb is significantly smaller so the phosphorus is glowing brighter to compensate for the smaller surface area emitting light.

Fixture size, bulb selection, bulb age can all play a big part in the amount of light produced. Tubes will lose 30-50% of their light output over time. 4 new tubes can easily put out more light than 6 aged tubes. Different tubes can vary as much as 30% in lumen output right out of the gate as well! A softwhite tube can be around 2500 lumens while an ultralux daylight can produce 3500.. A T8 fixture could be smaller because of the narrower tube width than a T12 fixture. So it appears brighter if you look into the unit. Only a light meter can tell you for certain how much light the plants are receiving at their leaf surface.
 
Yes, using my camera's spot light meter on aperture priority mode, pointing at the leaves of 2 nepenthes, I get around f8.0 1/250 for the t8s and f8.0 1/25 for the t12s (which are aged a bit). So, it's about 3 or 4 more stops of light in photography terms.
 
How many lumens does a T-8 throw compared to a T-12? What is the actual difference between the two? Do T-8s come in daylight (6500K models) and still draw 40 watts each?

Would 4x T-8s in this "tall ceiling" reflector be equivalent (or better) of 2x 95W Power Compacts (3 ft long) for mounting over a 3ft tall landcsape vivarium that I have in it's planning stages?

Typical T8 48" run on 30 or 32 watts and will be 2600-2800 initial lumens for a daylight tube.
Typical T12 48" run on 34 or 40 watts and will be about 2700 lumens for the 34watt energy saver and 3200 lumens for the 40watt (daylight for both)
So you can see the T8 is not all that much less when compared to energysaver T12 but is noticeable with the old 40watt T12

Neither a 4tube T8 or T12 fixture will put out as much light as 2x 96w power compact fixture. . I am correct in thinking you are talking about the 34" long bent tube bulb that is typically used in the aquarium trade and not the spiral type of Compact Fluorescent?
For both the 4 tube T8 and T12 fixture, estimate about 4x2600 lumens = 10400 lumens vs 2x 96w power compact at 8000 lumens each for 16000 lumens.
 
  • #10
You mentioned your new fixture also has a very nice reflector which will make a HUGE difference. Especially since most of the light from a round fluorescent tube is not produced in the direction you want it to go! Deffinately worth the $ for a high quality reflector if your plants are relying on the artificial light.
 
  • #11
Thanks for the info Tony! Yep these are the 34" saltwater reef tubes (6500k). Since I already own this setup I go with it.

Have you any lumen info on the 105 watt spiral compact Floros that fit a regular light socket? They're about 12" long and daylight color temp but none of the ebay sellers mention the lumen rating. And I've not seen them in shops yet. I've noticed those 26 W spirals seem really dim.

I always make a reflector out of aluminum flashing in any light hood / setup I build. The angles may not be perfect but it at least helps from loosing that light to the canopy top. Side reflectors (on an empty fish tank or garden area) are awesome helpers too. My Neps colored right up when the foil flaps were added to my tanks.
 
  • #12
Thanks for the info Tony! Yep these are the 34" saltwater reef tubes (6500k). Since I already own this setup I go with it.

Have you any lumen info on the 105 watt spiral compact Floros that fit a regular light socket?


Something like this?
105w spiral cfl
That one there says 5000 lumens

Here you can compare a few different ones. Looks like they can go upwards of 7000 lumens too depending which bulb you end up with
More 105w cfl spirals
 
  • #13
Thanks again Tony!
Yes, on that second link the ones at the top "Energy Miser", they've got the straight tubes on the twisty screw in ballast-base. The lumens don't look too shabby on paper.
 
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