The bulb should be replaced every 8000 hours. In NC, that means about every other pond season. So, typically if you use it from May through October, you will need to replace it by the end of the second season or beginning of the third one. Hope that makes sense. You may also want to check the quartz sleeve. If it is dirty or has hard water deposits, etc., the light cannot reach the algae to kill it. Flow rate is also affected by a dirty pump, dirty media, clogged tubing, etc.
Date published: 2018-06-06