Difference between DE and Mogul based MH?

[fkshiu]

There's no such thing as an "electronic HQI ballast". When dealing with MH ballasts there are four basic types:

1. Magnetic probe start (aka TAR or cap and coil)
2. Magnetic pulse start
3. HQI
4. Electronic

Generally speaking, you'll get the most PAR out of HQI ballasts but they will use a lot more energy at the same time. Electronics use less energy but put out a bit less PAR. Magnetics are in the middle usually. Electronics are smaller, lighter, make no noise and generate very little heat.

SE bulbs are pretty much jacketed DE bulbs. This allows SE bulbs to be run without a separate glass UV shield which DEs require. The shield can cut down on PAR.

Different bulbs may require different ballasts. For example, most European SE bulbs require a pulse start ballast because they have no internal ignitor. Electronic ballasts can run any bulb of the stated wattage.

Certain SE bulbs, like the Radium 20K 250w, are specifically designed to run on an HQI ballast. Therefore, you are not overdriving them at all on an HQI ballast and they will last a lot longer than 9 months.

A good resource to help you decide on your bulb/ballast combo is Sanjay Joshi's site:

http://www.manhattanreefs.com/lighting