Bulb Life

[speccialj922]

I basically want to know what the lifespan of vho, pc's and MH bulbs is. NOT how often you replace them, because im sure there is someone out there still running 5 year old PC's etc, but IDEALLY, how long is the lifespan of each of these types of bulbs.

(Im thinking of going MH, and i know everyone is going to say to do it, but $ is tight and i'd need to find a pretty darn cheap used setup to want to switch right now...)

[Paul B]

MH lamps last about 40,000 hours which is quite a few years. We use them in parking lots but they will be useless after a year in a tank although you can still use the old ones if you have a dark parking lot.

[speccialj922]

thanks paulb. just for clarification, "a few years" - does this mean before it burns out, or before the color shifts enough to be rendered useless?

[rdnyva]

I think what he's asking is how many hours before they have to be changed out, not how many years they last since everyone utilizes different photo periods. I'd like to know the answer to this also.

[speccialj922]

bingo:)
basically, when SHOULD I change bulbs?
(I'm not going to tell you how long I let my vhos run)

[JKDMan]

Mh bulbs should be replaced every 7-9 months IMO some people say a year

[Paul B]

Correct. The color temp will change over time but the lamp will burn for 40,000 hours or more. I have one in my yard going on about ten years now and it is on all night every night.
It would be useless in a tank

[Jefe12234]

There's no set time that a bulb should be replaced. The bulb will gradually lose intensity and possibly shift in spectrum. It's just a matter of what percentage of initial intensity your prepared to lose, and then whether you can properly acclimate the tank to a new bulb if necessary. If you have plenty of intensity to begin with and can acclimate the tank to a new bulb properly, then you can go a long time before replacing the bulb. If, on the other hand, you have just enough light to begin with, then you may want to replace the bulb earlier.

Of course certain bulb and ballast combinations will generally last longer than others. I have a 250w Phoenix on an HQI ballast that has been running for 14 months now and still grows coral quite well. Then there's the general concensus that Radium bulbs should be replaced after 6 months. I think you just have to go by experience. When the bulb appears dim, shifts to an unfavorable spectrum, or no longer grows coral well, then you should replace it.

[speccialj922]

well i just bought 4 new vho's, and i dont believe i'll be returning them. however i am thinking of switching to MH next year instead of replacing the vho's again. this of co(urse is assuming that i can get a MH retro for dirt cheap, AND can find the time to make a new hood for my 50g... :(

is switching to MH going to cost significantly more per year to light my tank? (I'll probly still run 1 actinic vho and maybe do 2 175s or 250s bulbs)

[korndogg091]

it really depends on how long you keeps your lights on per day. Some people only have MH and might run them 8hrs while some have vho and do a dusk to dawn effect. maybe only running the MH 4hrs while letting the vho's run 2 hours before and after the MH are on. I was running my xm 20k for 8 hours and i found colors in my corals faded and corals in the sand bed stopped getting enough light after about 8 months. i just added new bulbs and im already seeing things color back up and look healthier.

[speccialj922]

with 1 or 2 vho's running (doing the dawn and dusk thing) how long should 250w MH run? 5 - 7 hrs?

[Paul B]

If you run 100 watts of MH, VHO, or PC it is just about the same cost. You pay for watts.

[speccialj922]

i realize that, what i am curious about, is if i run a bulb or 2 of vho's to do the dawn and dusk thing (that i am already doing w/ my vho's), how long do i need to run a MH bulb?

[Paul B]

I would run them for about 12 hours

[nyvp]

I would think 8 hrs is prob the average of what most people run them

[bureau13]

Regarding bulb life, someone did a test over about 2 years and published the results here a couple months ago. They were using Phoenix 250W 14K bulbs, and found that after the initial dropoff over the first couple months, the bulbs were pretty consistent for I think it was almost 2 years. This is significantly longer than the conventional "wisdom." Of course, I don't think you can extrapolate these results to different bulbs...even other ballasts might impact this, using the same bulbs.

jds

[Aquarist007]

<a href=showthread.php?s=&postid=10875020#post10875020 target=_blank>Originally posted</a> by Jefe12234
There's no set time that a bulb should be replaced. The bulb will gradually lose intensity and possibly shift in spectrum. It's just a matter of what percentage of initial intensity your prepared to lose, and then whether you can properly acclimate the tank to a new bulb if necessary. If you have plenty of intensity to begin with and can acclimate the tank to a new bulb properly, then you can go a long time before replacing the bulb. If, on the other hand, you have just enough light to begin with, then you may want to replace the bulb earlier.

Of course certain bulb and ballast combinations will generally last longer than others. I have a 250w Phoenix on an HQI ballast that has been running for 14 months now and still grows coral quite well. Then there's the general concensus that Radium bulbs should be replaced after 6 months. I think you just have to go by experience. When the bulb appears dim, shifts to an unfavorable spectrum, or no longer grows coral well, then you should replace it.

Excellent post--very practical----------

I'm up to one year now--with no signs of decline in coral growth(but all lps's)
Two questions from your post--
How do you acclimate the tank properly to a new bulb

How do you know if the attinics have shifted to an unfavorable spectrum.

[Jefe12234]

Well, I know of three ways to acclimate a tank to a new bulb. If you have a pendant that can be easily raised, then just raise it up and slowly lower it over several weeks. Some people use layers of window screen and then remove a layer every few days or so. I suppose you could lay the window screen on top of some eggcrate which could be cut to fit inside your tanks trim. The third way is to reduce the photoperiod to maybe a couple hours at first and then slowly increase. The idea is that it takes a couple hours for photosynthesis to ramp up, so by cutting the light at this point the coral doesn't have a chance to produce excess oxygen which is what causes them to bleach.

As for actinics, I don't use them but their purpose is to bring out the fluorescent pigments in corals so I'd replace them when they no longer make your colors pop or when the tank is losing its overall blue tone. You could test it by turning them off and on and watching any green corals in particular (many happen to be highly fluorescent).

[Aquarist007]

<a href=showthread.php?s=&postid=10887778#post10887778 target=_blank>Originally posted</a> by Jefe12234
Well, I know of three ways to acclimate a tank to a new bulb. If you have a pendant that can be easily raised, then just raise it up and slowly lower it over several weeks. Some people use layers of window screen and then remove a layer every few days or so. I suppose you could lay the window screen on top of some eggcrate which could be cut to fit inside your tanks trim. The third way is to reduce the photoperiod to maybe a couple hours at first and then slowly increase. The idea is that it takes a couple hours for photosynthesis to ramp up, so by cutting the light at this point the coral doesn't have a chance to produce excess oxygen which is what causes them to bleach.

As for actinics, I don't use them but their purpose is to bring out the fluorescent pigments in corals so I'd replace them when they no longer make your colors pop or when the tank is losing its overall blue tone. You could test it by turning them off and on and watching any green corals in particular (many happen to be highly fluorescent).

great tips---thanks for the practical advice.

I have a coral life canopy with attinics and halides---I guess from your post that they should not be changed at the same time--that would be too much of an adjustment??