When to replace CF bulb?

[RISEANDFLOAT]

I have had my light going for 11 months now. It is a 65W Coralife Compact Fluorescent fixture. They seem to be pretty popular at least in my area. My question is when should I replace the fluorescent bulb? I read the other day that fluorescent bulbs only have 50% of their intensity after being used for a year or so. Is this true for compact fluorescents?

[rkilling1]

I have read a post from someone on here about a response they received from coralife about this question. It stated that the bulbs should be replaced between 9 and 10 months of use. Of course your photo period has a great inpact on this time. I know from growing aquatic plants, that letting the bulbs go for too long will only lead to disaster!

Replace the bulbs a little early and waste a couple bucks or waste all the time to clean up your tank and remove dead corals? I guess that's a quesiton that everyone has to answer.

I'll see if I can dig up the post.

EdIT: This post was in relation to planted tanks, but will suffice for corals as well. Shifting of the spectrum is a bigger worry then losing PAR in a planted tank. I have no idea how that would effect corals.

Originally Posted by evercl92

I've seen this question asked several times, and also seen various answers. So, I went ahead and emailed Coralife to find out when the bulbs should be replaced. Here's what I recieved:

"
It actually depends on the plant species. You can go as long as 16 months for some species, and as little as 6 months for more sensitive species. On average if you change them out every 8 to 10 months you will be good.

Regards,
Rob M.
Product Lines Tech. Support Dpt.
Central Aquatics
"

@Innovator: Are you telling me that going for 5 years on the same bulbs would still allow all the corals to live. I wouldn't think so. My post was an extreme and nothing more. Corals can and will die if not provided enough light. The point was, and remains, that IMO I would rather change the bulbs then possibly lose some of my corals.

[Innovator]

If you have access to a PAR meter then you can pinpoint just how much life you can expect from your bulb; otherwise, yearly replacement has been the norm for quite some time. In addition, exaggeration in relation to coral death by the previous post. i.e. highly unlikely.

[Kurt_Nelson]

For what it's worth, I change out my CF every 6 months. And I notice an obvious difference when the new bulbs go in.

[evercl92]

I had sworn I had made a post like that... thanks for digging it up.

[RISEANDFLOAT]

So when I do replace this bulb, do I have to worry about killing or "sun-burning" any of my corals with the new light? Also I previously bought some button polyps from my lfs. I got a rock with about twenty polyps on it, but only half of them are opening up. If I get this new bulb will they slowly come back? I have had them for about four days now. Will they eventually die if I keep them in there unopened?

[usmcmarc]

got a rock with about twenty polyps on it, but only half of them are opening up. If I get this new bulb will they slowly come back? I have had them for about four days now. Will they eventually die if I keep them in there unopened?

IME, you should just leave them. They should open up eventually. As long as your water parameters are in good shape.

So when I do replace this bulb, do I have to worry about killing or "sun-burning" any of my corals with the new light?

No..you should not have any "sunburn" issues, as long as they are the same wattage as the last ones.

[cmor1701d]

How long is your daily photo period?
I changed my CF's every 6-7 months running them 10 (10k) - 12 (03) hours/day. At nine months algae growth started taking off.

You should not have any significant impact (other than good) from replacing the bulbs.

[Innovator]

If you are worried about "burning" you can replace one right away and the other 2 wks after to allow for adjustment.

Rkilling: The original post questioned bulb replacement after 11 months of use. You stated, "Replace the bulbs a little early and waste a couple bucks or waste all the time to clean up your tank and remove dead corals?" Corals, for the most part, will not perish within a year's time due to not replacing the bulbs nor will they suddenly decline because their use extends just over a year. Where your 5yr input came from, I have no idea as it is not relevant to this particular question and even if it was, I have personally worked on aquariums with halides extending the 1.5yr mark with no losses of sps plus subjected my personal aquaria (lps/soft) without any direct or indirect light for 1.5wks without any losses.

[melosu58]

Moved to General Hardware and equipment discussion.