I have seen it written that PC bulbs should be replaced yearly. Is this really necessary? I understand that most typical fluorescent bulbs quickly lose their brightness when new and then very slowly dim. PC bulbs for room lights claim long lives of many years but obviously are not lighting corals where lumens are as important. I generally have changed my PC bulbs when one goes out-the if it ain't broke don't fix it philosophy- (I'm mostly lighting soft corals with lower light requirements) but am wondering if I should be more diligent.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
How often to replace PC bulbs
- Thread starter Jim5
- Start date
They do last a very long time if you don't throw them out after a fixed time period. I have one that lit for 12 hr/day, and it is 3.5 yrs old.
The main issue is that with the dimming effect of aged bulb, you are using the same amount of electricity for smaller output. So somewhere between the first day, and when the bulb dies, it is more economical to replace the bulb (bulb replacement cost) than having to deal with lowered output (higher electricity cost due to more wattage is needed to achieve the same output).
I feel once per year is reasonable.
The main issue is that with the dimming effect of aged bulb, you are using the same amount of electricity for smaller output. So somewhere between the first day, and when the bulb dies, it is more economical to replace the bulb (bulb replacement cost) than having to deal with lowered output (higher electricity cost due to more wattage is needed to achieve the same output).
I feel once per year is reasonable.
David,
With the low wattage of PC bulbs, mine are 96w, it's hard to believe I would make up the cost of the energy loss with the high cost outlay for the bulbs but I've never tried to figure this out. I did hear that as the bulbs get dimmer, algae growth may become more of a problem but I cannot recall why. Maybe a wavelength issue?
With the low wattage of PC bulbs, mine are 96w, it's hard to believe I would make up the cost of the energy loss with the high cost outlay for the bulbs but I've never tried to figure this out. I did hear that as the bulbs get dimmer, algae growth may become more of a problem but I cannot recall why. Maybe a wavelength issue?
It can be a bit misleading by the phrase "wavelength issue." Wavelength does not change, it is the spectrum of the bulb's output that changes, assume there is more than one type of phosphor being used in the bulb.
Anyway, if the electrity/bulb replacement cost is low, then one should get more, but older, bulbs in the hood if the space is available. Say a replacement bulb costs $50, then assumes the spectrum and intensity do not change much over the remaining life of an old bulb, you calculate the amount of time $50 can buy in electricty, assume the intensity/spectrum metric give you a 50% discount over the "utility function" of the bulb.
The concept can be a bit complicated, and I am sure some of you can do a better job in explaination than I did, but the notion that I want you to go away from is that a bulb burn up more cost in electrity over its lifetime than the cost of the bulb. This is certainly true for low-cost bulb (incandenscent, halogen, and other non-reef bulbs), and without actually going thru the calculation myself, I *think* it also hold true for PC bulb that we use in the hobby.
Maybe some of you who have more time can run thru the number using a spreadsheet or matlab, and see if my hypothesis is correct. AFAIK, nobody had done these type of empirical calculation on PC bulb used in the hobby, so I am sure many people will appreciate the effect.
Anyway, if the electrity/bulb replacement cost is low, then one should get more, but older, bulbs in the hood if the space is available. Say a replacement bulb costs $50, then assumes the spectrum and intensity do not change much over the remaining life of an old bulb, you calculate the amount of time $50 can buy in electricty, assume the intensity/spectrum metric give you a 50% discount over the "utility function" of the bulb.
The concept can be a bit complicated, and I am sure some of you can do a better job in explaination than I did, but the notion that I want you to go away from is that a bulb burn up more cost in electrity over its lifetime than the cost of the bulb. This is certainly true for low-cost bulb (incandenscent, halogen, and other non-reef bulbs), and without actually going thru the calculation myself, I *think* it also hold true for PC bulb that we use in the hobby.
Maybe some of you who have more time can run thru the number using a spreadsheet or matlab, and see if my hypothesis is correct. AFAIK, nobody had done these type of empirical calculation on PC bulb used in the hobby, so I am sure many people will appreciate the effect.
Okay, I'll change my PC bulbs every year as this seems to be the concensus. I'm just not usually fond of replacing something that seems to be working. I don't have a radiometer, so I cannot really tell how much brightness the bulbs have lost. I do bring my bulbs to the local hazmat, btw, to avoid the environmental impact.
Sponsor Reefs
We're a FREE website, and we exist because of hobbyists like YOU who help us run this community.
Click here to sponsor $10:
