View Full Version : T12 vs T8

12-14-2007, 10:33 PM
I have a 48" electronic ballast (double) that has had a Powerglo and a Sunglo combo in it for a long, long time (ie: several years). I don't leave this light on for very many hours per day (3-6) but still figure these bulbs must be well past their half life and decided to replace them.

I picked up a new pair of T8's (Powerglo & Sunglo) but when I went to do the switch I realized the old ones were T12's. I slapped in the new T8's anyways, but didn't find them any brighter than the old ones. I got out my camera and took a couple of controlled shots with each set - and the histogram seemed to confirm my impression: the 'brand new' ones were no brighter than the old, they were even slightly less bright!

Are T12's that much brighter than T8's to start with? I would hate to think I was sold a worn pair of T8 bulbs as 'new' (although the way the management of this lfs has gone in recent years I could almost believe it...). I don't think it's an issue with the ballast (or could it be?). It's around 10 yrs old.

12-16-2007, 06:52 AM
Not sure of the "brighter" T8's, but they do use less energy. I think, (and could be wrong), that the T8 is supposed to match the T12 in output, with less energy usage.
I also have both sizes in the same lengths, and can't really see a difference.
I run mine overdriven 2X, and I can see the difference doing that versus normal, but still not between T12 and T8
The ballast could be an issue if it's not designed for T8's, and I actually did get "got" at an lfs one time with used bulbs sold as new. Management made it right and had the excuse that an employee made a mistake. They put the old tubes in the new sleeve during change outs to keep them from getting broken (makes sense). Mine happened to get put in the new rack instead of in the back for disposal.

12-17-2007, 08:25 PM
I think, (and could be wrong), that the T8 is supposed to match the T12 in output, with less energy usage.
Thanks for your response, that's what I thought too...

There is nothing on the ballast about T8 vs T12. From what I've read if they were not designed for T8's the bulbs would flicker or not work, it wouldn't just be a question of brightness...

I'll try taking the bulbs back, but the current management of this lfs are really unlikely to admit a mistake or do right by the Customer... it's just not in their business mentality. They would accuse me of trying to return my old ones rather than admit error on their part. I stopped buying fish there when they told me "our customers don't know or care" about purity or quality. Dry goods that are not in a sealed package are now off the list as well... In fact anything that I can find elsewhere is now off the list...

I think I'm more peeved by the fact that this used to be a half-decent lfs before the change in management a few years ago. [/end rant]

12-18-2007, 12:03 AM
[/start rant] Don't you think you would strive to have the best/coolest/most reputable store possible???? If I owned a shop, I would not stop. Why settle for junk? You go to some stores, not only mega-shops, but dedicated fish stores, and their selection is terrible. They don't care or put forth the effort. [Sorry DW, hope your lighting situation gets resolved]