Old Bulbs = Algae

[chris88]

The shift in spectrum isn't the issue with old bulbs, it's the major drop in par. Its on average about a 30% drop in par after 6 months and sometimes a 50% drop after a year. This happens with t5's or halides. This isn't a debatable issue. There is a lot of data on the decrease in par so its a fact and not a conspiracy. I would not suggest running any type of bulb for longer then a year unless you are doing a fowlr tank. I change my t5's at about 9-10 months.

[Myka]

Originally Posted by chris88

The shift in spectrum isn't the issue with old bulbs, it's the major drop in par. Its on average about a 30% drop in par after 6 months and sometimes a 50% drop after a year. This happens with t5's or halides. This isn't a debatable issue. There is a lot of data on the decrease in par so its a fact and not a conspiracy. I would not suggest running any type of bulb for longer then a year unless you are doing a fowlr tank. I change my t5's at about 9-10 months.

It is a debatable issue because your numbers aren't right, but that's a different topic. Please explain how lower PAR affects algae growth...?

[chris88]

My numbers are close to right on, but it does change depending on the type of bulb and cooling of the bulbs. Just check reef central there are numerous threads on par decrease over time. I guarantee you my numbers are on par with what everyone has been testing and coming up with.

I didn’t make any mention of how par effects algae growth. My comment was directed to the people who said there was no need to change their bulbs unless they burn out. I already address effects color spectrum has on algae growth in my previous posts.