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What is "high quality" about high-quality T5HO lighting?

Discussion in 'Lighting' started by growitnow, Mar 12, 2011.

  1. growitnow

    growitnow Lifetime Charter Member
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    Hi,

    I read many posts saying that T5HO lights provide "high quality" light, say in comparison to compact flourescents.

    I read many many posts (especially here on Barr Report, and especially for T5HOs) when folk say they're having algae issues that in addition to increasing CO2, 'you have too much light - raise the lights or use fewer bulbs'.

    These indications seem to raise a contradiction:

    On the one hand, there is a general sense that T5HO lighting is better and of higher quality (or so it seems). On the other hand if T5HO lighting has the tendency to overpower tank needs, then what's so great about them in comparison to compact flourescents (aka, why not use compact flourescents in the first place).

    Thanks,
    growitnow
     
  2. pepetj

    pepetj Lifetime Members
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    T5HO lamps represent a major improvement in lighting system since they provide a lot of light (intensity wise) in linear lamps. Compact Fluorescents used for aquariums are indeed T5 lamps, yet the efficiency of them is questionable due to geometric and electro-physics to name two.

    T5HO, and T5NO, both come in linear tube shapes, which means a perfect circumference radiates light that with efficient reflectors, end up directing a lot of the emitted light where we need it to go: through the water column in several angles.

    Compact fluorescents, even if technically are T5 and HO present a different geometry since its built with two linear lamps placed adjacent and too close to each other which are connected together at one end through a smaller diameter through a hollow glass piece. Some of the light emitted through the circumference of these two adjacent linear tubes is lost as far as not reaching the water column.

    For some electro-physical issues that I don't understand fully, it seems that the design of Compact Fluorescents (using a smaller diameter hollow glass tube that allows the gas trapped inside the two linear sections to emit light) requires more frequent striking from the electrodes. The loss in quality and quantity of light emitted from a Compact Fluorescent decays faster than with a fully linear lamp. I think some aquarist suggest replacing them every six months. Consider linear T5HO lamps, they last easily 18 months providing quality light in aquarium use. T5NO last easily one year, as T8 lamps do.

    So here we have two major advantages in using T5HO or even T5NO instead of Compact Fluorescent: Better light distribution through out the water column (enhanced noticeably with the use of adequate reflectors -geometry and optical wise) and longer life of the lamp.

    What may be too much light is not a straightforward issue. Take high-light loving plant like Hemianthus callitrichoides... how many T5NO or CF lamps would be needed to keep them comfortable? Would a dual T5HO fixture suffice? Maybe those fixtures with four T5HO lamps make sense for reef tanks only and most freshwater planted tanks likely do well with single T5HO fixtures but what about tall tanks? It may or not work.

    The"Hoppy Chart" is one of the most useful comparative charts I've seen in a while since it allows us to compare fluorescent lamps for aquarium use considering the distance from the lamp to the water surface and the height of the water column as well.

    I just got myself the Apogee MQ-200 meter so I can make informed decisions regarding adequate lighting systems for each tank individually. It may be that two T5NO lamps work better for certain tank than a single T5HO in terms of getting to that range of balance between ligth, CO2, temperature, and nutrients.

    There may be a reason why Compact Fluorescent lamps are being replaced in the aquarium trade after all: It's not cost-efficient anymore.

    Pepetj
    Santo Domingo
     
  3. SuperColey1

    SuperColey1 Guru Class Expert

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    T5NO and T8NO lamps will last longer than T5HO lamps. T5HO lamps are overdriven hence they give less lumens per watt. They do give more lumens per inch though.

    T5HO is aimed at situations where it is good to get more light without having to increase the amount of tubes however the trade off is you lose some efficiency.

    T5NO and T8 will last longer than T5HO if used on the same sort of ballasts namely electronic. Most T5NO systems will already use electronic ballasts so the majority will last longer.

    T8 setups especially the older ones tend to use magnetic ballasts which 'flicker' start the tube and it is this method which degrades them quicker.

    The best tubes for our purpose are T5NO however because of the popularity of T5HO even amongst those in our hobby T5s are not so easy to source.

    CFs have loads of issues with them. They get really hot, sometimes melting their end caps or even the holder. Restrike is a mojor problem due to having to direct light away from 2 tubes so reflector design is very difficult and is not going to be able to compete with linear reflectors.

    AC

    AC
     
  4. growitnow

    growitnow Lifetime Charter Member
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    Hi, thanks for the excellent and detailed replies. This is interesting and informative.

    Essentially what I am hearing is: “You get more light with fewer bulbs, and the bulbs need to be changed less often.”

    "T5HO and T5NO are more efficient"

    (1) More efficient because of geometry of bulb.
    Single round tube so more consistent light emission across length of tube & therefore more uniform dispersion. Compared to CF tube with inconsistent light emission so some light emitted “is lost”. (i.e., T5HO/T5NO produce more light, and more consistent light). Though with decent reflector the latter problem would presumably be minimized.

    Frequent striking from electrodes: mumbo jumbo to me.

    (2) More efficient because of cost.
    Replace CF every 6months, replace T5HO or T5NO every 18months to a year.

    (3) More efficient because more lumens per inch.
    Again, they produce more light.

    (4) CFs get hot.

    Not sure I follow the restrike issue. If light strikes the reflector, what difference does it make if the bulb is a single bulb versus CF dual bulb. Though I don’t know what design difference there is for a single-bulb T5 (“linear bulb”) reflector vs. for a dual-bulb (CF bulb) reflector. I would have guessed similar.

    That T5HO/T5NO are more efficient (they produce more light with fewer bulbs), and, that CFs are not adequate - are different statements. No one implied the latter. But given the apparent favor of T5HO/T5NO this almost seems implied. Though perhaps it makes sense if T5HO/T5NO produce just as much or more light with fewer bulbs (and possibly better penetrating light, though I'm not sure I follow logic on that one), and have to be replaced less often.

    There is more to the excellent responses above, but I'm just trying to distill the advantages, as I currently have woefully pedestrian CFs. :)

    growitnow
     
  5. SuperColey1

    SuperColey1 Guru Class Expert

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    Nope I think you've gotten a little confused. The post above mine said that T5HO lasted longer than T5NO which in turn last longer than T8 which is wrong. There was a thread on APC or Planted tank that states this however they are not judging like for like and the HO lasting longer than NO is incorrect.

    Basically assume that we use electronic ballasts for all lighting. That means we are now judging like for like.

    NO (Normal output) tubes last longer than HO (high output) tubes much as an engine driven at 50mph continuously will last longer than an engine driven at 100mph.

    So it is T5 and T8 NO that last longest. T8HO and T5HO last a shorter time.

    The CF is basically a T5HO bent in half so is not efficient already as an NO. Couple that with the heat and other wastage with them and that means they are also less efficient as a T5HO.

    Now there are differences in opinion but I personally think you are better off having more NO tubes and spacing them out than having fewer HO tubes. I think you can use less light and power if you space the lights out better.

    To throw some more confusion into this is the magnetic ballast issue. When people test and then state that T5NO and HO last longer than T8 they are incorrect. It is nothing to do with the T8 tube but how it is powered that causes this. To test how long tubes are good for and compare them side by side means using the same method of powering them.

    So run a T8 on magnetic and a T5NO or HO on electronic then yes the T8 will not last very long at all. Also run the T8 on electronic and it will now last a similar time to the T5NO and longer than the T5HO.

    Another misnomer is the T8 HO (or VHO.) For example a standard 2 ft T8NO is 18W. However you can get 20W HO versions. Are these any better? Not really. Most setups are powering them with 18W ballasts anyway so there is no gain.

    So the simple answer is NO lasts longer than HO.
    NO enables a better spread and IMO means you can actually use less wattage than HO.
    T8 is fine but if you want them to last then run them on electronic ballasts and then they will last as long as T5 and longer than T5HO.

    Ho is great in reefs where they are trying to pack so much more light than us into their hods. It means they can squeeze lots more light into their canopys. It is also good for warehouse lighting. lol. IMO defeats the object for our purposes.

    AC
     
    #5 SuperColey1, Mar 14, 2011
    Last edited by a moderator: Mar 17, 2011
  6. Jim Miller

    Jim Miller Lifetime Charter Member
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    I keep monkeying around with the configuration of my Catalina 4 bulb fixture. I'm next planning to add a NO 6500K bulb along with a 10K bulb to the middle two locations and install a switch to allow either of them to be lit for maintenance viewing or silly blue light viewing.

    I may take it another step and install two more NO 6500K bulbs in the outer locations currently occupied by the HO 6500K bulbs to let me run 3x NO rather than 2X HO to reduce the light from the current 80par (est from hoppy chart) to 40-60par.

    My testing indicates the HO ballasts installed by Catalina (one per bulb) drive the NO bulbs just fine at their rated output.

    My realllly big monkeying will including putting some relays and a microcontroller inside the lamp housing to act as the builtin timer. I'll reprogram the timer via a serial port connected PC when it needs to change (not often). Most of the time the only thing connected will be a single power cord. The micro will have battery backup for clock maintenance when power fails.The switches will remain in place as overrides. That will have to wait until after my daughter's graduation in May. There's lots of room inside the housing and the hardest part of this (for me anyway) is programming the PC interface in VB.net.

    Jim
     
    #6 Jim Miller, Mar 14, 2011
    Last edited by a moderator: Mar 14, 2011
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