thanks, that site has a hell of a lot more than the one's I could find.
Not sure which one to go for now,
PL11W Marine Blue 20k Lighting Tube for AquaStyle 510 Aquarium or the
PL11W mix Triphosphor 7.1k & Blue 14k for AquaStyle 510 Original Aqua One replacement Triphosphor and Marine Blue Mix Flourescent Lighting Tube for AquaStyle 510
Brilliant Under Sea Effect....:Fish: