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Thread: What do you think of this light?

  1. #9
    Av8tor1's Avatar
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    Saw this coming...

    You are probably running into humidity issues with the fan running.

    The cold spot temp of T8 compared to T5 is typically 35C as opposed to 45C. However, the cold spot is in a different location. In the T8 and T12 format the cold spot is in the center of the bulb, whereas in T5 it is close to the end. Since the cold spot is in the middle of the T8/T12 it usually poses less of an issue for the cp'er.

    Bulb output is proportional to cold spot temps. This is why they may appear dim when first turned on while ambient temps are low.

    The 4' T8 are also 32 watts as opposed to the 40w of the T12 and the 54w of the T5HO. The advantage of the 32w T8 over the 40w T12 is the decreased amount of glass, phosphor and the increased reflector efficiency. These efficiencies are then taken to a whole new level with the T5HO format.

    At first glance you would think the lower wattage of the T8 compared to the T12 would mean a reduction in heat. Not necessarily so, T8's do have a lower wattage but also have less thermal mass to dissipate their heat

    CFL's can be T5, T4 or even T2... so their temps can be even higher per watt of power

    You have basically run into the common catch-22 that comes along with boosting light levels. More light in a given area equals higher temps. Higher temps require more air circulation. More air ciculation usually results in lower humidity. Lower humidity then requires it's own supplementation.

    There are already some really good, in-depth threads on this subject that you should look at if you haven’t already.

    Most lights will grow plants... but if you want all you can get, then those extra photons comes with a price,

    suggested article: http://www.aquabotanic.com/lightcompare.htm

    Did that help or just muddy the waters LOL,

    There are rarely black and white answers

    Here are two pictures of the exact same plant, grown under the exact same bulbs using the same fixture. Only the reflector is different.
    (these are high PUR (and low lumen!!)T12's)





    HTH's
    Av

  2. #10
    twigs's Avatar
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    Well that solves it. I'm moving to Albany so I can grow my Ceph's outside.

    Well maybe not. I did go out and get a rack of shelves to use as a grow light, along with some T8 fixtures. My plants were pretty cramped underneath the first light I bought, and if I do decide to start experimenting with TC, I will need the room. I'm sure I can find a use for the other light, but for now I think I'll go with the 'standard' 48" lights.

    And WOW that is quite a difference. What are HTH's? Is that a brand/type of reflector? Do you have a recommendation on where I could pick some up?

  3. #11
    Av8tor1's Avatar
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    HTH = "hope this helps"

    line your shop light's reflector with mylar


  4. #12
    twigs's Avatar
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    Av8tor1

    Thank you so much for your help. I was going to get some mylar to put around the sides/back anyway, so I can use that to line the reflectors. Right now the temp is right below 80 without the fan!

    I still might use the humidifier while I wait on the mylar to come in.

  5. #13

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    Just wondering if anyone else used this light and how well it worked for them?

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