Perhaps an Article on MH?

[Gauge]

I search around and find info here and there on MH lights, but I still leave with questions. I see that a lot of people ask these things repeatedly, so perhaps we can make this thread the beginning of an article on MH's. That way when we hear these questions we can give them complete answers with a simple link. The following are some of the things I would like to see in the article...

1) Why MH's are important
2) Every way to categorize MH bulbs, ballasts, sockets, Kelvin ratings, etc (for example, I have no idea what HQI, pulse starters, magnetic starters, moguls, etc mean)
3) Strengths and weaknesses of these categories
4) What all is needed to set up a MH system
5) Any other details worth considering
6) Suggestions about where to buy MH equipment

The information I'm really looking for is categories. I know what a lot of the things mean, but I don't know what differentiations go together. For example, if someone told me what 10,000K meant, I wouldn't necessarily understand that you can't have a 10,000K bulb that was also .03 actenic. So, if I knew what a HQI bulb was (and I don't), I have no idea if that can be mogul bulb or not. Can anyone enlighten me on these things even if no one is interested in making an article about it?

 

[Gauge]

Oops. Can someone delete one of these two threads?

 

[reefrunner69]

The problem with an article on MH is finding someone with enough knowledge on the subject to write it and feels comfortable putting it out there for everyone to read and critisize. I'll think about doing one, but don't count on it anytime soon, lots of research to do first.

 

[SquishyFish]

I have several articles on the subject. I will see if maybe I can condense them into one (and give credit to the original authors.)

This is an excerpt from an article that I wrote for our web site:

There are two scientific ways to measure light... lumens/lux and PAR. First, let's define each term.

Lumen: The unit of flow of light, from any one source.

Lux: The amount of light striking a surface.

PAR: Photosynthetic Available Radiation

Lumens and Lux
The light emitted from any source is then distributed over the area to be illuminated. The illumination is measured in "lux", a measurement of how many lumens falls on each square meter of surface. An illumination of 1000 lux implies that 1000 lumens are falling on each square meter of surface.

This is what we generally refer to when we say wattage. Its the difference between a 40 watt bulb and a 250 watt bulb. To the human eye, the 550 nanometer (nm) range is the wavelength that we see as the brightest.

PAR
Just as humans need a balanced diet, plants and corals need balanced, full-spectrum light for good health and optimum growth. The quality of light is as important as quantity. Plants are sensitive to a similar portion of the spectrum as is the human eye. This portion of the light spectrum is referred to as Photosynthetic Active Radiation or PAR, namely about 400 to 700 nm in wavelength.

For our purposes, PAR is the intensity of the of the usable light as it travels deeper through the water. PAR is important for several reasons. It tells us which light is best suited for our plants and corals and it tells manufactures how to avoid a yellow looking bulb (550 nm wave length appears yellow). Guy Comstock (Bang Guy) gave this example:

"An example would be a 110 watt URI VHO actinic bulb. It has 1/10th the lumens of a standard daylight florescent bulb but 2 1/2 times the PAR. If you just went by Lumens then the Actinic bulb would appear to be useless for a reef tank."

Its my understanding that the best PAR rating (top to bottom) is Metal Halide (MH), T5, Very High Output (VHO), Power Compact (PC) and then Normal Output (NO).

K Rating
Now...throw in the last twist in the whole thing, the K rating.

K is what tells you what color the light is (color is determined by temperature of the bulb. Thus the reason for the Kelvin rating system). Nothing else. Sunlight is 5.5 K. The closer to 0 you get (lower K rating) the more yellow the light... the further away from 0 (higher K rating) the more blue the light. Many hobbyists like the look of 10 or 20K bulbs... anything lower tends to give the aquarium a yellow cast.

 

[SquishyFish]

HQI bulb was (and I don't), I have no idea if that can be mogul bulb or not.

The other questions you posed were either answered in my above post or need a little study for us to answer. HQI simply means that the bulb is being over driven to burn brighter. There is some debate about what "HQI" actually stands for and where is came from, but..just know that it means that its running the bulb brighter and hotter than normal. You need a ballast that is specifically designed to run a HQI lighting system. Many people will run them on their propigation tanks.


That help?

 

[SquishyFish]

Excerpts from an article found on an Reef Keeping Online Magazine. Author unknown:

The main types of reef tank lighting are categorized by their types of bulbs, these are: Very High Output fluorescent (VHO), power compact (PC), metal halide (MH) and mercury vapor (MV). Metal halide and mercury vapor are in a class of lamps known as high-intensity discharge (HID) lamps, which rely on the evaporation of a solid material inside an arc tube to create light. Lamp manufacturers utilize a wide array of materials to create different color temperature lamps, and the availability and stability of these materials are the main contributors that impact the life and price of a bulb. In this article, only the metal halide and the Iwasaki mercury vapor lighting options will be discussed.

Common Metal Halide Lighting Acronyms:

MV =Mercury Vapor
LPS =Low Pressure Sodium
HPS =High Pressure Sodium
HID = High Intensity Discharge, MV, MH, LPS and HPS
DE =Double-ended, most MH lamps in the U.S. are single-ended with a Mogul base
SE = Single-ended
HQI = Metal Halide Lamps with a high CRI and/or European DE and some SE lamps
OCV = Open Circuit Voltage
HX-NPF/NX-HPF = High Reactance Autotransformer
CWA = Constant Wattage Autotransformer
CW = Constant Wattage
CCF = Current Crest Factor
Acronyms Based on Bulb Position
• BU = Burn the lamp with the base up
• BD = Burn the lamp with the base down
• HBU = Burn the lamp horizontal to base up
• HBD = Burn the lamp horizontal to base down
• V = Burn the lamp with the base vertical
• U = Burn the lamp in any (universal) position
• HOR = Burn the lamp with the base horizontal


Lamps, Sockets, and Lamp Holders
In choosing lighting, it is generally accepted that increases in wattage result in increases in illumination. Consequently, the first thing to determine is what wattage lamp to use, and how many are going to be needed to provide thorough coverage for your tank. In most cases, one bulb is required per 1-2 ft2. Lamps are available in 70, 150, 175, 250, 400 and 1000-watt configurations, as well as color temperatures ranging from 4200K to 50,000K (see this article for interesting comparisons of various color temperature bulb combinations). There are three types of bases that are utilized to provide the main points of electrical contact to the bulb; these bases are known as mogul, medium, and double-ended. The most popular type of metal halide lamps in the U.S. are single-ended and have an E39 screw type base, which is commonly called a mogul base. Most European lamps imported into the US have an E40 screw base and are compatible with the E39 lamp holders. Some low wattage lamps (70 and 150 watt) use a medium base, which is the same size found in typical incandescent bulbs. There are also double-ended lamps that require a pair of lamp holders, known as Rx7S for 150 watt and Fc2 for 250 watt lamps.
Metal halide operation can be broken up into two separate phases, startup and steady-state operation, and the amount of power consumed by the system during these phases is different. Starting up the bulbs always requires more power than steady operation; up to several thousand volts may be needed. All MV and most MH lamps have an electrode located at one end of the arc tube to provide additional current to the lamp while it is starting up. These types of lamps require an Open Circuit Voltage (OCV), in which two times the lamp voltage is needed to initiate and sustain the arc. Some newer MH lamps (mainly European) have no starting electrode, so in addition to the OCV, the arc is started by a high voltage (4 kV or more) pulse that is provided by an igniter.
Unlike normal incandescent bulbs, HID lamps cannot be run directly off of 120 VAC like an incandescent lamp and take several minutes to warm up and come to full brightness. If the power is interrupted while an HID lamp is on, it will take several minutes to restrike the arc and cause the bulb to begin burning again.
Lamp Type Warm-Up Time Restrike Time
MV 5 - 7 minutes 3 - 6 minutes
MH 2 - 5 minutes 10- 20 minutes

Lamp Manufacturers:
• Osram Sylvania
• Iwasaki
• Venture
• Coralife
• Aqualine Buschke (AB)
• Radium
• Ushio / BLV (in Europe)

 

[Gauge]

Can anyone at least suggest some products for me? I'm looking for an inexpensive 175w MH bulb that is 10,000K (and it has to LOOK like a 10,000K... I've seen some 10,000K's that looked like 20,000K's and almost looked actinic). After seeing some of the differences in bulbs, I'd rather go on a suggestion than what I read in articles.

 

[Sparky]

Based on information and experience in "regular" lighting, HID lights such as MH are matched to the wattage by the ballast they use. There are instances where "overdriving" the lamp with a different ballast have worked, although be concerned that when you do "overdrive" a lamp rated for lets say 175 watts and make it burn hotter you also rick the chance of that lamp exploding. I have seen this happen, purely by my electricians making a mistake and placing the wrong wattage lamp in a light.

Also, some companies make lamps that will work in a different setting. GE makes a MH lamp that uses a HPS ballast, and is designed to work that way. I believe it is called ChromaFit. It comes in 250 and 400 watt, but it uses a S50 and S51 HPS ballast respectively. Now these are specially designed lamp to work this way, not all lamps can be used in all ballasts.

Hope this helps shed some light on the MH subject.

Mike

 

[SquishyFish]

Ebay..."Cool Touch Lighting systems" is the system I used. XM bulbs 10k are great. I would suppliment with actinics though.

If you just wanted a product suggestion thats all you had to ask for. I was under the impression you wanting some good information and articles since thats what you asked for.

 

[Gauge]

I personally wanted the product suggestion, but I feel that an article would really benefit everyone here since I see MH questions asked a lot.

Is XM a brand or a type of bulb?

FYI - I have a 2X55w PC ballast and a full actinic and full 10,000K bulb on it. When I get the MH I will switch to two actinics and I should be in good shape.

 

[reefrunner69]

http://www.aquariumadvice.com/bulb_comp/

XM is the brand.................................................................................................................

 

[SquishyFish]

Brand...

I see your in Dallas. You can swing by Saltwater Paradise. They usually have them in stock. I'll warn you though...Scott isnt exactly a people person.

 

[Gauge]

Neither is Bill at Boutique Pets, but I still go.

It's a long drive, but for MH's I'll make the journey. Thanks a bunch.

 

[SquishyFish]

No problem...