Using Shop Light Fixtures

[C'Man]

I hooked up a shop light over my freshwater "river tank." I had two 4', 40 watt flourescent bulbs in it. One bulb was a plant bulb and the other a reptile bulb. The reptile bulb is a bit thinner than the plant bulb, if that matters. After two weeks, the fixture failed. The bulbs still work in a different fixture and regular bulbs do not work in this fixture. The outlet is good. Other appliances work in it. So my conclusion is that the fixture/ballast just failed. My question: is a $7 shoplight fixture not "worthy" of two $20 bulbs, or is this just most likely a random failure?

Thanks for any input.

[beviking]

The reptile bulb is thinner? Is one a T12 bulb and the other a T8? Apparently, you can run T12 or T8 bulbs on a ballast used for T12's, but they have to be in pairs, 2-T12's or 2-T8's. If they're both the same, I think you just got a bumb fixture. I have 2 of the $7 fixtures, running 2 T8 bulbs each and they're working fine, been 2months now. Hope this helps.

[C'Man]

No, one is a T-8 and the other a T-12. So that must be the problem? My electrical ignorance is showing.