[Owen Stubbs]

Seems the light from my single fluorescent tube is no where near as bright as it used to be. It is only a few months old. Is the cause likely to be the tube or ballast (or something else)?

 

[ianiwane]

That is normal for a flourescent light. After it burns in, they do tend to get dimmer. It will stay at where it is right now till it pretty much burns out.

 

[Owen Stubbs]

I'm talking maybe half the original light output here....

 

[ianiwane]

type of light? CF, T5, T8? What kind of bulb? And how do you know its only half the light output. Do you have a par meter or a new bulb to compare it to?

 

[Owen Stubbs]

Modest light fixture - 15 watt, 18". I have no meter, this is just my own perception. I can tell you that I can look directly at the tube when on, and it is not annoying. Before, it was too bright to tolerate. Areas of the tank once well lit are barely lit now.

 

[Wasserpest]

The initial burn-in only takes a few hours, not months. Some bulbs degrade faster than others. Just buy a new bulb, see how it looks like, and after a few days of burn-in switch to your old one and compare the two.

 

[Owen Stubbs]

It was the tube, not the ballast. Significantly brighter, and this one is 6700K. Big difference in what everything looks like. Plants are considerably more green in appearance. Will be interesting to see if plant growth improves noticeably.