Aqua ultraviolet U.V. filter flickering?

[Toomnymods]

Well just spent like 240.00 for this 25watt u.v. filter /w wiper and plumbed it into my return for my 90 gallon, and plugged in the ballast and the unit just flickers.. It won't emit a solid stream of ultraviolet light (looking thru the endcap it lights up when lit properly supposedly) Anyone else have the same problem or is this how it works?
Thanks,
Chris

[Toomnymods]

Nevermind let it run all night and now for some reason decided to emit a full non-stop path of u.v. just took over a few hrs for the ballast to start working correctly.. still find it odd though..