Originally Posted by ReefNut
I just looked it up real quick and what they are is Power Compacts... which do well for soft reef or FOWLR aquariums.
Actually T6 lamps are very similar to T5 lamps. They have thicker glass and run at lower operating temperatures, but they are identical in lengths, wattages, and base types (G13) to T5 lamps, and can be used interchangeably. They are 1/8" larger in diameter, so some fixtures where the lamps are very crowded *might* have problems.
T6 lamps are being hocked as the "next generation" stuff, but only time will tell to whether they take on. Regardless, with them being interchangeable, it's no problem.