the fulham isn't too good at running T12 vho
's ... at best, the 220 watt WH 7 can only run a single bulb regardless of the wattage.
This is due to the fact the fulham cannot deliver the proper current to more than one bulb, which regardless of wattage is always 1.5 amps for a standard VHO
... the maximum current available from the WH7 is 1.8 amps.
smaller diameter bulbs like the T8 through T4 take less current because of a more efficient arc chamber, smaller diameter = less power wasted.