blue actinic replacement
 

How often should you replace the blue actinic lights in your system?

Depends on the type, PC are about 6-8 months T5 i would give a little longer 8-12. It also depends on how long your running them. Or if your following the zeo system every 3 months :lol:

Actinics are a lot easier to judge when to replace than standard bulbs - your coral colours will begin to lose their "pop".

what fkshiu said. The actinics are only for you as a viewer and not used by the corals for growth.