How often to change bulbs?

[monpeasch]

Hi,

I've got the "Outer Orbit 150 HQI" lights for my 90 gallon tank. My question is about how often lights need changing. Right now, they're on for about 7 hours a day. I have 2x150 10K power pak and 2x130 Dual Actincs. (Not sure if I got the terminology right on those..still new at this!)

Thanks!

[ScruffyRubicon]

As a rule of thumb:

MH once a year
Actinics every 6 months

[monpeasch]

Thanks!

[Geoff]

since actinics are not really needed, they are more for your benefit than the tank critters. you can run them untill you think they need to be replaced. i usually replace my actinics once a year when i notice that they are not balancing out my MH's as much anymore.

G~

[Loverotties]

Mh are more important,once a yr.