Power Compact source

Hi,
Im looking for a 55 watt 5000k power compact bulb for my aquarium. I
need the bulb w/ the square pin configuration. I can't find them
anywhere! Ive got two burned out ones, but I dont remember where I
got them. AHsupply only has the straight pin configuration. I really
need to get some light back on my aquarium and need to find these
bulbs as soon as possible.

thanks for any help,
Scott