just did a noob move. i just bought a high pressure mercury balast and fitting for £15 i just found out after i baught it. is the balast usable for anything else? a ballast is just a massive resistor right? would i be able to put a MH in it or many something smaller or larger that's the same effect? or does the ballast need to be correct for the bulb? why is this? is there any way to modify the ballast for use with other bulbs?