250 watt MH ballast(s)

[Slick Fork]

I'd be curious to see if the decrease in power consumption is comparable to the decrease in par. For example if the power consumption drops by 15% does the par drop 15% or is it more or less dramatic? Just how much more efficient would an E-ballast be over a traditional magnetic?

Also, what about electronic interference with other stuff such as televisions, radios, aquarium controllers,etc.?