Knoxter

Today my T5 fixtures came. They are indeed much cooler than the PC's. And there was only a slight difference in brightness, with the PC's being brighter. Both the PC'S and T5's are 10k. I will keep you posted on how the plants react.

Justin-Why use the 6700 over the 10k? The 10k is closer to natural day lght....Right?

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Marc

My frogs- Vanzolini, El Dorado (ong&gold), Cayo de Agua, Almerante, Gold Dust, Yuris, Imis, Inters, Taras, O Lamasi, Iquitos Vents, Varis, SI.


I appreciate everyone here. Without you, there would be no DFF. Thank you for your support.

spartcus

I think Justin uses 6700k over the 10k so he gets most of the spectrum that plants uses. Usually 6700k represent daylight and 10k represents dusk or dawn. 6700k usually is white with a pink hue to it. While the 10k is more of the bluish purple tint. Anything lower then 6700k on plants is a waste since most plants dont use that side of the spectrum which is usually the green and yellow.

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JustinF

Marc,

10k is a cooler light, actually closer to the light you would find in shade. 6700k is warmer, closer to what you would find out in the open, more unfiltered. Do you have a spectrograph for your 10ks?

I prefer 6700k because it has the red spectrum that in general the 10k are lacking. I prefer to stack as much usuable light as possible for the plants. I really don't find myself satisfied with a bunch of gree foliage and really like to provide adequate lighting to help the plants bring out as much of thier colors as I can.

Also, in general a 6700k has a better CRI then a 10k. In 10k lighting I find myself shooting close to a heavily shaded white balance. The less 10k in there, the more I can move white balance towards a sunlight setting as it's warmer.

Spartcus,

That is correct!

While 6700k does represent daylight, 10k represents cool white. Dusk/Dawn is actually much warmer lower K light, closer to 4-6K depending on conditions. That is the realy golden yellow light you see as the sun is low on the horizon.

The better a daylight bulb is, ideally 6500k, the higher the CRI, the whiter it should be. 6700k is not pure daylight, it's a touch green. 10k is cool white, so a little blue in appearance. Generally the significant difference is just the lack of red putting the majority of the balance to wards the high blue peak all fluorescents have due to their construction. If you prefer this color of lighting, the only thing you lose is the CRI and the red. But if you like it more, then by all means use it.

This is not the case. Many growers actually use HPS bulbs in the 2-4k range, they are usually as yellow as apple juice but have a TON of red output. This heavy slant in spectrum will encourage flowering in the plants while the 6500k range with it's increased blue light will produce vegetative growth. You will often find supplemental lighting in commercial greenhouses done by purpose, with the HPS installed in areas they want to flower/fruit plants while the MH will be used where vegetative growth is encouraged.

While neither source of light is commonly found in Vivs, the plants respond the same as a matter of biological principle. Many people don't like low K lighting for use in a display as they find the light ugly. Halogen & Incandescent lighting can have large yellow through red output based on their application and can be used in conjunction with other lighting in Viv applications such as the Exo Terra hood with 2 screw in CF and 1 Halogen configuration.

I imagine the hood is designed this way as the Halogen will throw out a good amount of red supplementing the shortcoming of your average CF, and heat output is useful in providing a basking spot serving to not only balance the spectrum of light in total but to provide warmth to reptiles as well. While there are many screw in CF's designed with as balanced of a spectrum as possible, many people don't use them due to their cost. Many people use the cheapest crap screw in CFs they can find which throw mostly green as that is the spectrum the human eye sees the best, which makes the bulb appear brighter.

Most screw in CF manufacturers do not even include a spectrograph immediately eliminating them as an option IMO as I cannot evaluate the output, I can't asses it's suitability for my application. I used to have a hand held grating Spectrometer but I lost it in a move so now rely on the spectrograph provided by the manufacturer and can no longer make my own measurements.

Hope this is not too confusing!

---------- Post added at 02:17 PM ---------- Previous post was at 02:15 PM ----------

I just thought I would add this link in case you guys want to geek out!!

A CD spectrometer

---------- Post added at 02:25 PM ---------- Previous post was at 02:17 PM ----------

I'm adding this chart to help people understand the spectrum output and where you would commonly see that light to better correlate the nm output with the visual que. The source will better help people associate nm output with bulbs, so you will know what nm comes from what source, and what bulbs have what sources.

Jeffdart

I use the daylight spiral cf 6500K bulbs. They are bright and work great.

SoCalPDF

I use 2 6500K daylight spiral CF bulbs in the zoomed hood..My plants are growing great, but I think the broms could use more light since my tank is 24" high..they seem to have lost some color..

Socalsam

ALl I have to say is if you want to get color back in your plants and reduce heat, stop fighting it and spend the money on T5. You will be happy in the long run!!!

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SoCalPDF

so how many T5 bulbs would I need over a 18x18x24? Just looking quickly, I found a few 20" fixtures with 2 bulbs, but its still only like 14 watts per bulb. Is that enough?

Socalsam

2 bulbs would be perfect.It actually may be more than you think , but will do good for your plants. If you can find a single bulb T5 then you could try that. I ATM am using some T12 with 2 bulbs. Because I use T12 i get allot more heat than you will , but i have a fan on my lights so it helps keep the heat down. I think once i get more Racks going I will invest in a misting system and better lighting.PC's and T12 are just to hot.

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Philsuma

Guys,

I need to upgrade from T-12 to T-5's.....

BUT

I need the "odd stepchild" size.....36" for my metal baker's rack systems.......and I need a decent cheap Walmart type price for them.

@ $20.00 each for the fixture and ballast and reflector.....is this possible???

Lowes? Home Depot? Mail order / internet?

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