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T5ho

Discussion in 'Lighting' started by rthomas, Jan 10, 2011.

  1. rthomas

    rthomas Guru Class Expert

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    Is 5 x 54W too much for a 120g tank ?
    That's 2.25 Watts per Gallon. Please advise.
     
  2. waj8

    waj8 Junior Poster

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    I would say it is not possible to say without knowing something about fixture efficiency and the CO2 setup. T5 light fixtures are potentially very efficient so it is probably a lot of light. Your fixture may not be the same as others though. I have 6 54 watt lamps and it was OK until I added Discus. Then I had some algae problems. I now only use 2 lamps for most of the day and it's better. One thing about having too much light is you can alway dial it back if you want. It would be nice to have dimmable ballasts so you could dial up the light level you want. They actually make them too. I see most people seem to just prefer to raise the light fixtures to reduce light levels. Seems rather inefficient to me.
     
  3. dutchy

    dutchy Plant Guru Team
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    I use just 1,5 WPG on a 180 gallon, and I can grow every plant I want. You have to ask yourself if you will be able to provide enough CO2 with that amount of light. If not, it will just give you algae and a high electricity bill.

    3 54W bulbs would be enough here.

    regards,
    dutchy
     
  4. pepetj

    pepetj Lifetime Members
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    As a rule of thumb: The light emitted per watt of energy used by T5 High Output lamp is twice as much light as the light emitted per watt of energy used by T8 Normal Output does.

    Do the math:5*54W = 270W T5HO; which translates into 2*270W = 540W of T8NO. Since we're talking about a four footer consider this: Would you place 13 40W T8 lamps plus one 20W T8 lamp on top of that tank if you could? We're talking about 4.5W per gallon here! That means your floor for dissolved CO2 will be quite high, as well as the demand of micro and macro nutrients.

    It is true that the valid and reliable way of knowing if a particular tank has little, enough, or too much light is by taking measurements with a Quantum Meter at different levels (e.g. surface, mid-tank, substrate).

    Since most hobbyist don't have a Quantum Meter, using the WPG guideline, although easily misleading (originally proposed with T12 Normal Output lamps which we rarely use today), at least let us know if we have the ball in the park or not.

    Things to consider:
    Tank Height. If your tank is indeed a 48"L then it's likely its water column height is greater than 20" you could end in the lower end by using this guideline.
    Water Turbidity. If you're keeping a blackwater tank, then you will likely need more light intensity to keep plants thriving.
    Plant species. If you're keeping plants that can make it only in the brightest lighting conditions then you need to keep that in mind.

    Pepetj
    Santo Domingo
     
  5. rthomas

    rthomas Guru Class Expert

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    Guys, thank you for your comments. BTW, I have pressurized CO2.

    Dutchy, I noticed that you have the Vortech MP40W wavemaker. I have 2x Koralia 4 for my 180 (another tank). I like the distribution of CO2 but I hate looking at plants with soft stems bending too much. Do you experience that with your Vortech ?
     
  6. dutchy

    dutchy Plant Guru Team
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    Yes, exactly. I removed the MP40 a few weeks ago, have not seen any differences so far. But I'm going to try an MP20, which flows only half of the MP40.

    Another problem was that plantgroups get compressed because of the high flow, and lose their lower leaves that way.

    At the moment the tank just runs on the flow of my two filters, which give a total of 400 gph. But I have to admit CO2 enters at both sides of the tank.

    regards,
    dutchy
     
  7. waj8

    waj8 Junior Poster

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    It is not true to say t8 lamps put out more light per watt than t5 lamps. T8 NO are typically better than T5HO in this regard. It is true that a T5 fixture is likely to be more than twice as efficient at getting light to the substrate of a tank. There is a vast difference in fixture efficiency from one setup to another.
     
  8. Jim Miller

    Jim Miller Lifetime Charter Member
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    IIRC there is some improvement in T5 lumens/watt but the primary improvement is in the significant reduction in restrike in the thinner lamp. The vast majority of florescents are used where
     
    #8 Jim Miller, Jan 10, 2011
    Last edited by a moderator: Jan 10, 2011
  9. dutchy

    dutchy Plant Guru Team
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    My proposal on using just 3 54 Watt bulb is based on PAR readings that I made, not on WPG basis.

    regards,
    dutchy
     
  10. Jim Miller

    Jim Miller Lifetime Charter Member
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    I wish PAR meters were more affordable. There just isn't a big enough market for a "pro-sumer" model to get into volume production and get the costs down. I suspect that in volume they could sell for $20.

    Until then the Hoppy chart is a wonderful thing!

    Jim
     
  11. dutchy

    dutchy Plant Guru Team
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    I think it's a guideline, nothing more. I measured 10 to 30% differences with various brands of T5's. The pink plant grow bulbs just put out 50% of PAR compared to a daylight bulb.

    These variations do not show up on Hoppy's chart.

    PAR meters are expensive, but irreplacable. Using less light after making PAR measurements will save money buying less fixtures, bulbs and less electrical cost. Even more important, a stable system which gives less worries.

    regards,
    dutchy.
     
  12. Jim Miller

    Jim Miller Lifetime Charter Member
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    Agree but a better guideline than wpg. The pink growlights always seemed like pyramid power, magic crystals or copper balance bracelets to me. Never saw any scientific basis for them.

    Jim
     
  13. waj8

    waj8 Junior Poster

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    The thing about your fixture Dutchy is that it may be very different than someone else's fixture. The shape and quality of the reflectors will make such a big difference. The measurements on your tank won't necessarily carry over to a different setup. Watts per gallon has always been B.S. It's nice to see that people are finally understanding that.

    It does look like LEDs are going to be next. Part of the reason is that all the light of an LED is reflected downward, even without any optics. Most of the light is also directed downward at angles greater than the critical angle required for light to enter the water. Another reason is because they are starting to finally exceed the efficacy of fluorescent lamps. Also the lamps are supposed to last longer. Although, the fluorescent lamps I am using right now have a 30,000 hour rating. LEDs may also have more PAR per lumen than many fluorescent lamps. If Dutchy can grow his truly beautiful plants under 160 watts of light, I imagine an LED fixture may be able to do it with 100 watts of light. My aquarium pump uses more juice than that. Too bad your choice of lamp colours with LEDs is even more limited than with T5HOs. Imagine someone trying to use 2 watts per gallon of that sort.
     
  14. rthomas

    rthomas Guru Class Expert

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    Jim, where can I get hold of that chart ?
     
  15. Jim Miller

    Jim Miller Lifetime Charter Member
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