Warning: Non-Standard Use of Metal Halide (MH) Lights

Discussion in 'Enclosures And Supplies' started by Dave Weldon, Aug 22, 2008.

  1. Dave Weldon

    Dave Weldon Avid Member

    Howdy All,

    From time-to-time, information pops-up suggesting the use of typical commercial (Home Depot etc.) metal halide (MH) light sources, with the glass safety filter removed, as a source of UVB for reptiles. The measurements that I've listed are a subset of the ones in the report made by Mrs. Frances M. Baines, M.A., Vet.M.B., M.R.C.V.S. Fran is part of the team that manages the http://www.uvguide.co.uk/ site.

    My super-quick summary: Using a MH with the glass filter removed has to potential to cause disease and death :eek:. Why remove the glass safety filter? The filter blocks both UVB and UVC. UVC is basically a biological death-ray. UVC at almost any level is dangerous/deadly. As an example, UVC is used to kill living organisms in water treatment systems.

    A very abbreviated summary of Fran's full report:

    MexLite double-ended 70watt 5500K metal halide (ONLY 70W!)

    Distance......8 inches....24 inches....What it means

    UVC uW.....57...............8..............Any at all is DANGEROUS (cancer etc.)

    UVB uW....814.............95..............50 is suggested to be towards the high-end for chameleons

    UV Index...151.............17..............Even a level like 14 represents desert sunlight. 151 = BBQ

    Posts regarding the data can be viewed here.

    In order to access the actual report FILE, you’ll need to join the UVB_Meter_Owners group. Joining this group could expose you to the ridicule of friends and family members who’ll now have direct evidence that you are truly too involved in your chameleon’s husbandry :eek:.

    The entire report file (if you have access permission):
    #1 Dave Weldon, Aug 22, 2008
    Last edited: Aug 22, 2008
    spatulars likes this.
  2. SoCaliSon

    SoCaliSon New Member

    I take this ridicule daily, and I am not even part of this group yet...lol...:rolleyes:

    I am trying to become more savy in the technical lighting mumbo jumbo, This is one area I want to focus on learning more about.

    Is it possible to give us laymans terms? Could you post an example of these metal Halide fixtures?

    I am curious... Cause I purchased my lighting fixtures from lowes. I would have thought it just depends on what kind of Bulbs you are using and noit the fixtures. I currently use 4 foot Double flourecent fixtures meant for shop or comercial use, I removed the plastic(not glass) cover that conceals the bulbs, I thought they would block the UV, and that they were only there for cosmetic reasons in the first place, and added a reptisun 5.0, and a GE Full Spectrum plant grow light. It sounds like you may be speaking of this sort of setup but I am not sure. Are my Chams safe?

    Thanks for the heads up Dave!

  3. Ryan Jarosek

    Ryan Jarosek New Member

    Awesome information Dave

    Metal Halide and HPS High Pressure Sodium bulbs are commonly used in the growth of plant life. Hydroponics. The Metal Halide bulbs produce light closer to the blue side of the spectrum where High Pressure Sodium produce light closer to the red spectrum. Both are great for growing plant life and Coral.

    Metal Halide bulbs produce a crisp clear blueish light where the HPS bulbs put off a more orange / Yellow tent of bulbs.

    The bulbs are completely different than any florescent tube lights. They would be a closer match to the Mercury Vapor Bulbs. I have dabbled in hydroponics a little.

    Not sure if this helps you at all Socali.

    Here is a link to a MH bulb http://77hydro-store.stores.yahoo.net/lum150.html

    EDIT : Here is a Wiki explination

    Metal halide lamps are used both for general industrial purposes, and for very specific applications which require specific UV or blue-frequency light. They are used for indoor growing applications, because they can provide the spectrum and temperature of light which encourage general plant growth. They are most often used in athletic facilities. Metal Halide lights are quite popular with reef aquarists, who need a high intensity light source for their corals. Another widespread use for such lamps is in higher end professional lighting fixtures, especially intelligent lighting. In this application they are commonly known as MSD lamps, and are generally used in 150, 250, 575 and 1200 watt ratings
    #3 Ryan Jarosek, Aug 22, 2008
    Last edited: Aug 22, 2008
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  4. rob408

    rob408 New Member

    I used to have a 150G full reef tank and used MH lighting. I would never think of using these for chams as they get very hot...these are very strong lighting. Was not aware of the UVC rays but I think people would be better off using 5.0 linear bulbs.

    These bulbs usually go from 150W to 400W depending on use. I've got a fixture in my garage which as 3 250W bulbs and I had to continuously run a chiller to keep my water at 80 degrees.

    Good info above though.
  5. royden

    royden New Member

    Is mercury vapor still safe or is it part of this group?
  6. Ryan Jarosek

    Ryan Jarosek New Member

    That is a good question. I know that the use of MV in Hydroponics is not very efficient. I would be curious how they measure up.

    MV bulbs can be used for breaking up molecules of chemical compounds and also has a germicidal effect.

    Looks like I have some googling to do. Now I am curious.
  7. Dave Weldon

    Dave Weldon Avid Member

    Howdy Joe,

    Typical Metal Halide bulb and fixture:



    What I can't tell from these sites is if any of them use the type of MH bulb that doesn't have at least the safety coating in addition to the fixture's glass filter lens :eek:. This issue does take us all the way back to why you don't remove the safety glass filter on Metal Halide lights in the first place :eek:.

    Your other question points right at the problem with some UVB fluorescent lamps and fixtures. With our typical Reptisun tubes, you can't have anything such as glass or plastic between them and your chameleon since it will filter-out all of the good UVB. There is no bad UVB or UVC to filter-out of our Reptisun 5.0 or 10.0 linear UVB fluorescent tubes :).

    Your chams are safe :).
  8. Dave Weldon

    Dave Weldon Avid Member

    Usually if you are using MH lighting as it was intended to be used (didn't remove the safety glass and/or bulb didn't have safety coating), you'll be safe.

    Some keepers properly use (safety glass installed etc.) their MH setups to light their entire chameleon room. With the correct color temperature etc., these lights make an excellent source for overall lighting.
  9. Dave Weldon

    Dave Weldon Avid Member

    Howdy Royden,

    MV bulbs are still as safe as they have ever been :rolleyes:. What I mean by that is that the good MV setups, when properly position, make good sources of useable UVB for chameleons. The trouble comes from using some of the dangerous MVs that have been coming out of China under odd-ball brand names or when using one of the good ones (Mega-Ray, T-Rex, ZooMed) but have it positioned too close.
  10. Dave Legacy

    Dave Legacy New Member

    I've got a MH fixture for a tank I haven't setup yet, but I have a little experience with them. That being said I wouldn't feel comfortable using them with herps unless they were placed at a great distance away and with dense foliage. MH is often used in reef tanks due to ability to achieve deep penetration that fluorescents cannot thus I'd think it would be awfully intense lighting w/o the element of water.

    Good post, Dave, as always.
  11. Dsignrguy

    Dsignrguy Member

    Here's something interesting

    I've had a mercury-vapor lamp since LONG before I had a chemeleon. I have a MV lamp from the 70's that is basically a 6.5' tall cylinder. it has a 250watt MV bulb and set of reflectors in the top so the light bounces off the ceiling and lights up the room.....this 1 lamp lights up my whole apartment. Well last week my ballast finally gave out(30 years aint too bad) and the lamp quit working. My chameleon suddenly started spending LOTS of time hanging out as close to his repti-sun uvb tube as he can get....something he has never done before.

    As soon as I can afford a new ballast, I'll let you know if he stops his new habit.
  12. Fate X

    Fate X New Member

    i have a 175watt mh light with the glass shield.it is as high on the ceiling as i can put it.it is a great ambient lamp for the chams room.its a future bright reflector with a digital ballast.
    it generates just the right amount of warmth on cool days.
  13. aquamac

    aquamac New Member

    Also important to note that the study was done on double ended MH bulbs. The European double sided lights are much smaller, and lack the protective cover that many big honkey lights that we have here do (which is why our bulb is so large). These bulbs produce a far greater amount of PAR for the same Watts. They are also more dangerous with UVB and UVC than their larger counterparts because they do not have this glass cover.


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