Cheap HO T5 fluorescent tubes

Discussion in 'Lighting' started by JamesC, 15 Nov 2007.

  1. JamesC

    JamesC Member

    Bexley, Kent
    Having decided to upgrade my lighting from T8 to T5 I treated myself to a secondhand 120cm T5 Arcadia Luminaire off ebay. It came with used marine tubes so I ditched those. Next was to purchase four 54 watt T5 tubes for it. Looking at the £15 plus for a single tube from online aquarium shops, which to me is an absolute rip off, I decided to look elsewhere.

    The problem with using normal tubes is that they are designed for lighting rooms and not fish tanks so a bit of trial and error was required to get the best results. There are lots of reports on what wavelengths are best for plants but nearly all this data comes from terrestrial plants and not aquatic ones. Most good daylight tubes seem to work well. Even so I always think it a good idea to have plenty of blue and red wavelengths which supposedly plants use most.

    Armed with my credit card I went and visited my favourite online light shop - - and purchased a range of tubes.

    Osram Lumilux 1149mm T5 840 Fluorescent Tube 54W - £3.00 (Excl. VAT)
    Osram Lumilux 1149mm T5 865 Fluorescent Tube 54W - £3.00 (Excl. VAT)
    Osram Lumilux 1149mm T5 880 Skywhite Fluorescent Tube 54W - £6.55 (Excl. VAT)
    Colour 96 1149mm T5 965 Fluorescent Tube 54W - £8.05 (Excl. VAT)

    Before I go into tube comparisons I'll explain a bit about lighting. CRI or Colour Rendering Index describes how a light source makes the colour of an object appear to human eyes and how well subtle variations in colour shades are revealed. It is measured on a scale of 0 to 100 where 100 is best. Kelvin (K) or Colour Temperature is a measurement in degrees Kelvin that indicates the hue of a specific type of light source. Normal daylight colour is around 6,000K. Reds have a lower K value and blues have a higher K value.

    So if you look at my first bulb it has a number of 840. This means that the CRI is between 80 and 89 and has a temperature of 4,000K. The first digit is the CRI and the second and third are the temperature. My last tube is 965 so CRI is greater than 90 with a temperature of 6,500K. Even with all this info it is not possible to really tell what the colour of a particular tube is going to be until you see it for yourself. Generally speaking the higher the CRI the better the light is at representing different colours.

    Enough of the bumpf and on to the testing.

    Osram Lumilux T5 840 Fluorescent Tube - This tube by itself looks quite white but when next to a daylight tube it has a definite orangy glow to it. Quite similar to the Dennerle Plant tubes that I've seen in the past.

    Osram Lumilux T5 865 Fluorescent Tube - A daylight tube but with a lowish CRI and is a bit too green for my liking. If you like a daylight tube on a budget then this is OK

    Osram Lumilux T5 880 Skywhite Fluorescent Tube - My favourite tube. Very bright white with a lovely hint of bluey purple.

    Colour 96 1149mm T5 965 Fluorescent Tube - The ones supplied to me were Philips. Very good daylight tube and could be used by itself if need be. Still a bit green for my liking but seems to give a nice range of colours in the tank.

    After experimenting with different combinations I ended up with two of the Osram 840's and two Osram 880 Skywhite's. This combination gives strong reds and blues without an overpowering green. I have the two 840's come on first and go off last to give a nice sunrise and sunset feel to the tank with the 880's coming on in the middle to give the tank a full sun feel.

    Am I happy, YES, especially when I've saved shed loads of money.

    Here are the spectra for the bulbs. Only difference is that I've put the Osram Lumilux De Luxe 965 in place of the Philips 965 as I couldn't find the spectrum for the Philips. Interestingly according to AE the Osram Lumilux De Luxe 965 is what Oliver Knott uses and unfortunately is unavailable in the UK, except for AE who import it.


  2. zig

    zig Member

    Dublin Ireland
    Nice writeup James, I have tried the Osram 865s and they grow plants very well indeed, some plants grew very compact under them compared to other lamps I have used.

    I will keep the 880s in mind for next time.
  3. George Farmer

    George Farmer Founder Staff Member

    Neat thread, James. Thanks for sharing.
  4. james3200

    james3200 Member

  5. Dave Spencer

    Dave Spencer Member

    N. Wales
    I remember when you linked to this site a while back and put it straight in to my favourites, but quickly forgot about it. Lamp replacement time is coming around and I will definitely be shopping here.

    The beauty of it is, at these prices, we can afford to experiment with several different tube combinations for the desired effect.

  6. JamesC

    JamesC Member

    Bexley, Kent
    Just a bump to say that I've added some spectra for the different tubes.

    Lamp Specs also sell T5 Grolux tubes which I may test next time I place an order. They didn't have any in stock when I placed this order. Grolux's are quite a pinky purple colour but are supposed to be good for plant growth. I used them with my T8's to great effect. The spectrum is similar to the daylights above except there is no green peak. Possibly in combination with the daylights they may work very well.


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