Well the bulbs are avaialble too 6500k..
But I can't OD it well :-(
But 15w into a 10 gallon tank, I should be fine anyways,
Fluorescent Lamp, Standard, Lamp Designation F15T8/D, Wattage 15, Lamp Tone Daylight, CRI 75, Rated Average Life Hours 7500, Color Temperature 6500, Initial Lumens 700, Mean Lumens 615, Starter Type Preheat, Lamp Length (Inches) 18, Base Medium Bipin (G13), T8, Diameter 1 Inch (26mm), Case Quantity 24
Grainger Item: 5V489
Price (ea) : $7.87
Manufacturer: GENERAL ELECTRIC
Mfg. Model#: F15T8/D