T10??
T12 and T8 you can regularly find, T10 I don't know about. A brief internet search shows it being sold, but you'll likely have a smaller selection of light spectrums. If you're going for freshwater, it might work well for you, but the saltwater spectrums will be harder to find. If you want to be able to pick up bulbs locally, you might want to go for something more conventional.