Ah sorry. It is T8. I think I will try an Osram 865. I have a 12 inche deep aquarium, and my understanding is that a 15W T8 should be enough for low light requirements.
sorry kenny thats wrong a t8 tube is 1" dia check googleIf it's a 3/4" or 8/12th of an inch across it's T8. T5 will be 5/8th of an inch across about thumb thickness.
you're right, it's done in 8th not 12ths. For some reason I got it into my head that it was 12ths due to the T12ssorry kenny thats wrong a t8 tube is 1" dia check google