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When to change bulbs (1 Viewer)

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Guest

How do you decide it's time to change your bulbs? Do you use a schedule or try to judge the bulb output?

Do PCs or VHO last longer? What is thier average lifespan along with that of MH?

Is there some type of weter that can be used that is not priced out of this world?

Thanks.
 
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AggieBrandon

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I'm not 100% sure on this but I have been watching my vho bulbs since I installed them last april. The ends are really starting to get darker now as one year approaches. I am getting ready to change them out but my corals are still doing perfectly fine. I have always heard that vho lasts longer than pc. I am going to follow this thread and see what else is mentioned.

Brandon
 
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ShaneV

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On my IceCap I go about 18 months between changing my VHO's.
 
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Guest

18 Months is the right amount of time to go on VHOs on a Ice Cap ballast.
There is more to it but I don't have the time to get into it today tommorow I'll give you a better answer.
 
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Guest

I agree. I typically only go about 12 - 13 months on my VHOs, and I go about 15 months on my MHs.

VHOs definitely last longer than PCs. I used to have PCs on my 75 gallon, and the light output of the bulbs would drop significantly within the first month, and were just about useless after 8 months. Compare that to 12 - 13 months (that I am going with) on my VHOs and compare the price and VHO is the way to go any day of the week.

MH ------- ~15 months
VHO ------ 12 - 13 months
PC -------- No more than 8 months
 
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Guest

Supposedly Icecap underdrives the bulbs so you get less intensity but longer life and that is why you could go 18 months. I figure once a year for everything and I'll always be fine.
 
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Guest

Like Tom said, you can get longer life out of VHO's with an IceCap ballast because they underdrive the bulbs. Same thing is true if you hookup 2 bulbs to a WH7 ballast, since that effectively underdrives the bulbs as well.

With MH, there are a lot of factors to bulb life. You will see bulb lifespans ranging anywhere from 6 months for Radiums to over 2 years for Iwasakis. Some of the factors involved are:

- Color temperature: In general, 20k bulbs have a shorter usable life than 6.5k or 10k bulbs.

- Bulb/ballast type: Properly matching the bulb to the ballast is an important factor in bulb life. If you mix probe/pulse start ballasts and bulbs, they will either not fire at all, or will fire very roughly. In the second case, it wears the bulb out quicker because they are not firing as effectively. Electronic ballasts really help here, because they can fire any kind of bulb so you don't have these issues.

- Overdriving/Underdriving: Like VHO's, you will find cases where bulbs are under/over driven which can effect the life of the bulb. The most common case is with DE lamps (commonly called HQI). A true 250w HQI ballast actually drives the bulb at 320w, so they don't last as long (although they are wicked bright). Running them on electronic ballasts prolongs bulb life, at the expense of a little brightness.
 
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Guest

Also a lot of people believe that they can make a MH lamp last longer by only using it for a few hours a day to simulate mid-day. However, most of the stress on a MH bulb doesn't come from time burned but times fired.
 
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Guest

Is there any way of testing them? Or do we have to go on a time basis?
 
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Guest

I know that there is a tester that you can get called a Lux Meter. This unit measures the brightness of light at a certain place. However, for comparison you would have had to take baseline measurements when you first installed the bulbs to get a sense of what kind of drop off you have seen.

The Lux Meter only measures intensity, and not spectrum. I don't know of any tester that will measure the spectrum of the bulb other than a spectrograph/spectroanlyzer, and those are reserved for research, and not home use. This is what you would need to measure the change in the spectrum of the bulbs, which is as important if not more so that the intensity.

As far as I know, time is the best method. You will notice differences in your tank as the bulbs age. I know that I see different algaes breaking out when the bulbs are worn out. I also see less polyp extension from the corals.

Jim 8)
 
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Guest

Lighting dats base

Now this is useful information & why I joined MARSH :) .

Thanks for posting guys.

Can we start a data base to include type, brand, cost & summarize the lighting recommendations, bulb life, etc. based upon actual field test & use by MARSHians? Maybe other critical tank components also?

It would be nice to have a "research" bulletin board to save & share this valuable information.
 
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