[dapellegrini]

I dunno - I have been using T5HO for a couple of years now in 3 different fixtures, 1 Catalina and 2 Tek lights. I also know a number of folks in our local group that run Tek lights and I will say that typically after about 9 months T5HO's are SIGNIFICANTLY dimmer than new bulbs. As such, I typically replace mine every 9 months, as do other folks that I know.

I do not believe it has anything to do with the bulbs. I have been through Giesemann, Aqua Medic, CoralVue, UV Lighting, etc all with similar results.

I cannot say that the bulbs are NO GOOD after 9 months, but they definitely give off significantly less visible light - very easy to see the difference if you plug a new bulb in next to the older ones and light them up.

I have heard that it is T5NO's that can last you up to 24 months - perhaps because they are not being overdriven...

 

[dapellegrini]

Huh, those Coralife fixtures are the ones that take T5NO's...

 

[dapellegrini]

You can get the Planta bulbs from Aquacave.com - I typically mix them 50/50 with 10k's and really like the results. Definitely my preference over other 5-6.7k bulbs.

I wonder where this 18-24 month life of T5 bulbs came from. IME it is completely false...

 

[dapellegrini]

Perhaps all of our old references about the effective life of aquarium lighting are more hear-say than fact? If I understand you right, T5 bulbs do NOT have an effective life of 18-24 months, yet this is the "common knowledge".

This would confirm my experience as well as the experience of a number of local hobbyist in AZ...