T5 Lighting Question

[Pescador]

The number is the diameter of the tube in eighths of an inch.

ex. T8 = 1" dia.
T12 = 1.5" dia.

For regular T12's the wattage is 5/6 of the length in inches. ex. 48"=40w

Here's a link to some info http://members.misty.com/don/f-lamp.html

I think aquarium NO's usually have waterproof endcaps but you can buy those seperately.