Quote:
Originally Posted by Becca
TThe only thing I forgot to ask was the bulb life.
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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)