Read the question.The guy asked how long they last, not how long they are good for.Even if he asked how long they are good for ,it would depend on what he need it for.For example i personaly use PC's bulbs on my fish tanks ,refuge and reef well over a year .I'm not telling you to do it.People recommend changing PC's every 6 months but they don,t do it .The PAR starts to drop and the color starts to shift after about 6 months. Most people recommend changing compact fluorescent bulbs every 6 months for a reef tank. I've never heard of one being good for 2 years.
Read the question.The guy asked how long they last, not how long they are good for.Even if he asked how long they are good for ,it would depend on what he need it for.For example i personaly use PC's bulbs on my fish tanks ,refuge and reef well over a year .I'm not telling you to do it.People recommend changing PC's every 6 months but they don,t do it .
I've asked some people about this and they say the best way is to measure the par from the new bulb that way you can get a benchmark. After a certain time period re-check the par to see how different. But not everyone can afford a par meter![]()
(cali reef)You sure know how to sink a ship man .:dead1: +1 on the t5's, i think i'll be getting some myself.If that's case, wouldn't it LAST until the moment before it "dies"??:splitspin
There is no guaranty and impossible to predict how long it will "last". Some can last 3 days, some three years.. No point in this question..
I really think he meant "How often to change" PC bulbs.
My answer would be "Change to T5's as soon as you saved up for a new light setup":lol2:..