reference : Metal Halide Ballasts, which one is which?

When I was looking for info on ballasts, I run into a post on an aqu forum. here is the link and the text:
http://reefcentral.com/forums/showthread.php?s=&threadid=201570
Metal Halide Ballasts, which one is which? Answers here:
I have seen countless lighting threads asking what each MH ballast is or what bulbs work on it. I orginally posted this in another forum to answer another member's question. I thought it was best posted here. If there's anything I missed, or have incorrect, please let me know.

250w example:

Probe start: ANSI: M58, core, capacitor
Pulse start: ANSI: M138, core, capacitor, ignitor
HQI: ANSI: M80, core, capacitor, ignitor
EYE: ANSI: H37, core, capacitor, actually a mercury vapor ballast
Electronic: ANSI: none, metal box with wires

probe start will run american bulbs with ignitors built into the bulbs like coralife and venture bulbs. some german and euro bulbs will run fine on these, but without an ignitor, the bulb struggles to light and bulb life may be decreased. also reliabilty goes down.

pulse start will run the german/euro bulbs (ushio, AB, radium, etc.) these bulbs don't have built in ignitors, so the ballast has the ignitor wired into the circuit. the ignitor provides the high voltages needed to fire the bulb. you can run probe start bulbs on these ballasts, but the two ignitors may try to fight each other and possibly cause a fire.

HQI ballasts are similar to pulse starts in their wiring and ability to run bulbs. the output is a little higher which is meant to run the double-ended bulbs (commonly called HQI bulbs). people run mogul bulbs on these and they run a little hotter and brighter because they are being overdriven. this in turn shortens the life of the bulbs.

EYE ballasts are mercury vapor ballasts. they are similar to a probe start ballast, but the only bulb you can run on these are Iwasaki 6500K bulbs (because these are actually MV bulbs, not MH bulbs like most think). the ballast will damage MH bulbs if you try to run one on it.

Electronic. ahhh, the great electronics. these will run any bulb at the rated wattage: probe start, pulse start, iwasakis, DE (double ended-HQI). if you think you might change your mind in the future, get an electronic. you can change bulbs to whatever you want and not have to worry about the ballast being the wrong type. electronics run cooler (a magnetic MH ballast will burn your hand if you touch the coil after it's been running for awhile). they also use less energy.

Additional info:

175watt:
Probe start: ANSI: M57, core, capacitor
Pulse start: ANSI: M137, core, capacitor, ignitor
Electronic: ANSI: none, metal box with wires

400watt:
Probe start: ANSI: M59, core, capacitor
Pulse start: ANSI: M135, core, capacitor, ignitor
HQI: ANSI: SON AGRO, core, capacitor, ignitor (this is actually a 430w HPS ballast used primarily in hydroponics)
EYE: ANSI: H33, core, capacitor, actually a mercury vapor ballast
Electronic: ANSI: none, metal box with wires
I would like to add a few things:

The HQI (ANSI M80) will overdrive most North American lamps but not all single-ended lamps. The Radium 250-watt blue lamp is one that is designed for this ballast.

The M80 is best suited for European double-ended and most single-ended lamps.

The Pulse Start 250 (ANSI M138 / M153) will underdrive most European lamps. I personally don't see a good reason why this ballast is offered for the aquarium market. Currently there is no lamp that will operate properly on this ballast for aquarium use.

The pulse start 400 underdrives almost every European lamp (except the Radium blue lamp) but uses the correct starting method/voltage.

Currently the best ballast for Euro 400watt lamps is a true European ballast. The problem with this is the input voltage (only available in 220/230/240V) but this shouldn't be a problem for too long. A few lighting companies are working on 120V Euro type ballasts that won't need a step-up transformer.

I've spoken to a few people about the AB lamps in Europe (even the lamp manufacturer). These lamps are designed to be able to start at lower starting voltages than most European lamps. These lamps are equipped with a starting circuit (bi-metal switch and resistor) connected to an addition electrode (starting electrode).

The lamp chemistry causes the 175 and 250 watt lamps to have warm-up problems with standard probe start North American ballasts (Constant Wattage Autotransformer - CWA Type). These lamps require more voltage and amperage during warm-up than some standard ballasts can provide. With a standard ballast the arc becomes too thin and causes it to become unstable. Then the arc fails and starts again. Sodium usually prevents the arc from getting too thin but adding more sodium also changes the lamps performance in other ways.

The AB lamps will operate optimally on European ballasts. You'll get the best light color using a European or similar ballast (like M137/M152 for the 175W lamp and M80 for the 250W lamp).

Electronic ballasts are great for the lamps they are designed for.
An electronic 250W MH ballast will operate any 250W MH lamp like a 250W pulse start will. The reason is because both use a high Open Circuit Voltage (OCV) to start up a 250-watt lamp.

Currently more info is needed to know which lamp will operate optimally on what brand or model ballast. Personally I would like to see some testing done with 250 and 400 watt electronic MH ballasts. Currently I only have equipment to test electromagnetic ballasts properly.

It is very difficult to manufacture a 250 and 400 watt electronic ballast that will operate every 250/400 MH lamp optimally. This is because with 250/400 watt lamps you have 3 different kinds and each has different operating requirements.

Hope that helps

PaulErik