I don't know much about lights and lighting systems but let me tell ya a little story...

when I recently put together the big tank, I purchased a NOVA Extreme HO fixture manufactured by Current USA. After some time, one of the bulbs burned out so hubby went off the Home Depot or Lowe's (?) to get a replacement. He picked up whatever the one T5 was that they carry. Brought it home, put it in the fixture and every time we turned on the light, it blew the circuit breaker in that room! Took a closer look and saw that the wattage on the one from the local store is much lower than the one supplied with the fixture. I went online and found the HO T5 bulbs that Current manufactures for their HO fixtures and I'm awaiting delivery now. The first price I found was $16.89 each but I looked further and found them for $12.89. :crossfing

Don't know if this helps you at all, just thought I'd mention it ;)

Becca, there is always a lot of discussion about the longevity of the tubes. The producers recommend to change the tubes every 6 months as after this time 50% of the output has been lost, and this has been taken as the "Bible's words". However, since many of my friends into aquaristics and terraristics, as well as I, do not believe in the bible, some tests have been made in this respect (Note: private tests, so no data published, but distributed per voice-mail). We (well, actually my friends, as I just started to test my new lamps) have found that for T5 lamps, as well as triband T8, keep aprox. 95% of their original output after 5000h and 90% after 15000 continues work (this is more or less 7 and 21 months) If you consider that using the lamps in a 12/12 ritmus, this would mean about 14 to 42 months, however turning on and off (depending on the kind of ballast you use: analogue or electronic) reduce the bulb life. What my friends do is they change the lamps (T5/ triband T8) every 3 years, when the lamps have lost 20% of their original output. I am testing now my new lamps to see whether this is also applicable to orchids...

Furthermore, as Ross said, the only way to really know the bulb life is to measure and keep control of your lamps with a light-meter!


here a summary of the results of my friends (note: lamps were on non-stop):

T8 (standard): 85% (5000h), 80% (10000h), 75% (15000h)

T8 full spectrum: 90% (5000h), 85% (10000h), 80% (15000h)

T5/ Triband T8: 95% (5000h), 92% (10000h), 90% (15000h)

Yep Ross has talked to me previously about me needing to test my bulbs when they are new. I have started, but didn't have my light meter at the time I got the lights. So I will be starting fresh with the new set. My large orchidarium has the 6 biax (spelling?) bulbs ($10.5 FT55DL/950 OSRAM 55W 5000K 90CRI 2G11 BASE 55W/950 OSRAM BRAND) and they are a year and a half old. I currently have a dendrobium and a cattleya in bud, so I figured the lights can't be that bad can they? My other exo-terra has the 2ft 8 bulb T5 lights and the bulbs are currently a year old. I just ordered the replacement lights for the orchidarium and it is the 2 ft 8 T5's I am now shopping for. I haven't had much bloom with them but all the 'chids look happy and have new root and leaf growths!

Sorry I was out of the loop while this discussion was going on. To the best of my knowledge, all t5 HO lamps in US have a HO in the number somewhere. Mine actually say High Output on the end of the tube. I don't believe on purchasing based on price alone, especially not on the web. I tend to trust the sources I have used in the past. Once again, measure the light output with a trusted, calibrated meter, when the tubes are new and then again when you think it's time to replace them. Watch for any dramatic drop in output. Color temperature is another matter.