T5 question: 3100lm @4000K vs. 2850lm @6500K

Discussion in 'Lighting' started by Costa, 6 Sep 2019.

  1. Costa

    Costa Member

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    Hi team,

    I am looking at these two T5 lamps from OSRAM

    t5.PNG

    Do you have any advice on which one to go for? One is only 4000K but gives out more lumen than the 6500K. I understand that plants prefer 6500K but the 4000K one gives more lumen...

    Thank you so much
     
  2. ian_m

    ian_m Global Moderator Staff Member

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    Plants use light and don't really care too much about colour temperature.

    Your eyes care more than plants do. Choose tubes to make your plants (and fish) look good.

    Too lower colour temp and plants look dull & yellow and not bright (4000K and below maybe), too higher temperature and plants look white and washed out (above 10000K).

    I have a 8000K white and 6000k "colour" tubes in my tank. Looks too "pink", in my eyes with just 6000K tubes, which is why I added the 8000K tubes. Much better, plants look suitably pop out green and fish, especially cardinal tetras stand out well.

    Did you see this thread of tanks with different tubes.
    https://www.ukaps.org/forum/threads/cheap-ho-t5-fluorescent-tubes-update-with-photos.555/
     
    dw1305 likes this.
  3. Costa

    Costa Member

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    Thank you Ian

    Yes I did read through that thread, very useful. I will go for the 6500K then, I guess the 250lm won't make a hell of a difference.

    My light unit can carry 8x39 T5HO tubes, so 8X2850lm/800L=28,5lm/L which isn't that bad I suppose... (compared to the cheap ass led I had prior)
     
  4. ian_m

    ian_m Global Moderator Staff Member

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    That's a lot of light, what size is your tank ?

    This will help you decide what light level your tank will be running at. High light means CO2, ferts, weekly water changes, daily plant pruning etc.

    [​IMG]
     
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  5. Costa

    Costa Member

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    Thank you Ian,

    My tank is 200 x 60 x 60 cm + a 150L sump. Factoring in the substrate volume as well as the media and sponges in the sump, I arrived at a net volume of ca. 800L/190gal

    According to this 28lm/L is in the medium light range.

    [​IMG]

    The unit also has reflectors so in theory the output can go as far as 40lm/L, but then again there's a glass cover which will block some of the light.
     
    Last edited: 7 Sep 2019
  6. Zeus.

    Zeus. Member

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    If I was going to add just one spectrum tube I would go for the 6500K also
     
    Costa likes this.
  7. Costa

    Costa Member

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  8. Costa

    Costa Member

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    Could you guys recommend a couple of red/orange and blue lights in addition to the 6500K Sylvanias? I have access to ATI Actinic, Aquablue Plus and Purple Plus, but I don't think they are suitable for planted tanks?

    https://www.atinorthamerica.com/t5-bulbs/
     
  9. sparkyweasel

    sparkyweasel Member

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    The volume in the sump is irrelevant, as you won't be lighting it. :)
     

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