Old light algae bloom fact or fiction?

Old light algae bloom fact or fiction?

  • 6 months

    Votes: 2 5.6%

  • 12 months

    Votes: 18 50.0%

  • 18 months

    Votes: 6 16.7%

  • 24 months

    Votes: 6 16.7%

  • when they burn out

    Votes: 4 11.1%
  • Total voters
    36
Ron Reefman

Ron Reefman

Active member
OK, we've all heard, and many believe, the "˜old bulbs cause algae blooms' story. I don't want examples of how it happened to you, I want real scientific evidence.

What is it that changes and causes the algae? I've been asking this question for a while now and I have heard all kinds of answers. The bulbs get dimmer, the PAR value drops, the color spectrum of the bulb shifts to the red.

What does a lumen meter measure (lumens, I know, but just what is that)? How about a PAR meter? If it's a color shift, which bulb changes color? We use 6400, 10K, 14K and 20K bulbs in our tanks, which one shifts to the red that makes algae grow? Is there any way to measure the color shift with a reasonably priced meter? I can see how all fluorescents (PC, VHO and t5) could change in a similar way, but MH too? Oh, and leds last 10 years, don't age like all the other bulbs? And now I hear that PAR meters don't work the same on leds as they do on fluorescents and MH. Why?

I want science, not anecdotal evidence. Site a reference to a paper or a study. Help me understand the issue or lets debunk the myth.
 
Really? In the Advanced Topics Area and after almost a full day, no info. Now I'm really begining to think the 'old bulb' theory is 95% BS.
 
Give it some time, finding supporting research take time and effort to produce. A lot of people browse and post from their cell phones... which in turn are not great for doing research. Tagging along...
 
Ron Reefman said:
OK, we've all heard, and many believe, the "˜old bulbs cause algae blooms' story. I don't want examples of how it happened to you, I want real scientific evidence.

What is it that changes and causes the algae? I've been asking this question for a while now and I have heard all kinds of answers. The bulbs get dimmer, the PAR value drops, the color spectrum of the bulb shifts to the red.
Click to expand...


First you tell me you want scientific facts, then you go on to tell me that you won't be able to understand them.


Ron Reefman said:
What does a lumen meter measure (lumens, I know, but just what is that)? How about a PAR meter? If it's a color shift, which bulb changes color? We use 6400, 10K, 14K and 20K bulbs in our tanks, which one shifts to the red that makes algae grow? Is there any way to measure the color shift with a reasonably priced meter? I can see how all fluorescents (PC, VHO and t5) could change in a similar way, but MH too? Oh, and leds last 10 years, don't age like all the other bulbs? And now I hear that PAR meters don't work the same on leds as they do on fluorescents and MH. Why?

I want science, not anecdotal evidence. Site a reference to a paper or a study. Help me understand the issue or lets debunk the myth.
Click to expand...


If you really want to discuss this, then go and learn some background. It's not hard to find out about what lumens and par and all that is. It's not hard to find out about the two different photosystems used by corals and by algae. It's not hard to find out about what different spectra these two photosystems work best with.

It's also not hard to find out what happens to the spectrum of different lighting options as they age. I am sure that the effects are different with fluorescent bulbs and MH and LED.


Your post sounds really hostile. As if you have already made up your mind that this is a myth and you don't believe it. Then you list a whole bunch of the basics and say you don't know anything about them. I have a feeling this is why people don't want to answer. People who are both hostile and ignorant are never any fun to discuss anything with.

So my best advise to you is to run your bulbs however you see fit. If you never get an algae outbreak, then way to go. If you do, then I'm real sorry.


Once you have done some reading and have the ability to have this discussion, we can have it.
 
disc1,

I apologize for my post sounding "hostile", that wasn't my intent. I just find it frustrating that I read, or hear hobbists say, "Change your bulbs when they get to be XXX old." And if you ask why, the answer is, "Old bulbs can cause algae." If this really is the case, why hasn't somebody come up with a tool that I can test my lights with which will tell me when I should change my bulbs rather than an arbitrary time frame? And over a big system, bulbs can be a very expensive, reocurring cost. I have 5MH and 6 fluorescent bulbs over my 2 tanks.

I appreciate the links you've provided and I will read and try to understand a science that I admit is a little over my head (not that I'm stupid, I've just never needed to understand this much science about light before :headwallblue:). I did read the link about PAR and found it very informative and understandable.

One of your comments strikes to the heart of the matter. You wrote, "œIt's also not hard to find out what happens to the spectrum of different lighting options as they age." I briefly looked at all the links you provided (I admit I haven't read them all and will need to read them more than once or twice), but I didn't see anything that relates to the comment about what happens to the spectrum of bulbs as they age. And I guess more importantly, how can I test for that change?

Your first post"¦ sent me to Google"¦ which was cute"¦ OK, funny, but it also gave me a site that provided this info: "Algae colonies, in general, grows at wavelengths between 660 to 700 nanometers. Cyanobacteria is known to grow at much shorter wavelengths between 530-620 nanometers. Old bulbs and lamps will produce the lower wavelengths that will foster Cyanobacteria blooms."

So actinic bulbs fall pretty close to this 530-700nm range, some are even in it. Does that mean that some actinic bulbs are good for algae growth even when they are new? A 10K bulb is equal to 290nm which is way below the 530-700nm algae producing light range. That makes 14K (210nm) and 20K (145nm) bulbs even further from the "˜algae growth" numbers. As they age, do they really change that much? I'm not trying to be sarcastic or funny, I'm trying to understand. I assume I'm missing something? Can you help?

Ron
 
Ron Reefman said:
...I just find it frustrating that I read, or hear hobbists say, "Change your bulbs when they get to be XXX old." And if you ask why, the answer is, "Old bulbs can cause algae." If this really is the case, why hasn't somebody come up with a tool that I can test my lights with which will tell me when I should change my bulbs rather than an arbitrary time frame? And over a big system, bulbs can be a very expensive, reocurring cost. I have 5MH and 6 fluorescent bulbs over my 2 tanks.
Click to expand...

I think there is a really simple answer to this question.

It costs lots of money to make testing equipment. Then design it to fit a very hard model...

It must be shippable, if I told you I have a bulb testing system but it will take up a room in your home, would you still want it? It must be mass produceable, if not... they will be rare or hard to make and that in turn it worth more than you can reasonably spend on one. At least if your not the light bulb maker yourself... The same for materials to make it, must be cost worthy. On and on it goes...

Corporations that make these bulbs, spend big money to test them and their competitions bulbs, in many different ways... This data is in turn their consumable in which they use to make their bulbs better then everyone else's... You can see why they might not want that information to be seen by anyone else.

So in turn through many shared stories and road in on many reefers backs and busted many reefers wallets. People collectively using what little true data that was ever made available from manufactures and published in books, magazines and shared in clubs have reduced for you and all of us share... That you should change your bulbs at X months or years!
 
srusso,

Companies make lumen meters and PAR meters. They aren't cheap, but they are made and sell ( I have a PAR meter). So a meter that reads the color spectrum of the bulb is going to be too expensive?

And if the manufactures test their bulbs, why don't they provide how many hours they can be run before the spectrum changes? If I'm a bulb manufacturer, and I make a bulb that lasts longer than my competitors, wouldn't I make that a selling point? But none of the manufacturers even address the issue of regular bulb replacement. And the time frame most reefers quote is anywhere from 6 months to a year, no matter what kind of bulb (except leds which last 10 years).

Northreefer,

I had VHO bulbs over my old 75g system for 18 months, and like you, didn't have any issues either. In fact the PAR readings on the 18 month old bulbs was almost exactly the same as the new bulbs I got to replace them. That is part of why I want to understand this issue. The MH bulbs over my current 180g have been running for a year now and I have no issues now. Coral growth is as good as it has ever been and no algae (and I haven't run GFO in the last 6+ months).
 
Well, I can tell you for a fact that when I started to see hair algae in my tank and searched my records to find my bulbs were 14 months old, I replaced my old 150 watt Radium 20K MH bulb with a new 150 watt Radium 20K bulb. The color of the tank was significantly bluer and the algae went away. Did I take a spectrum analysis of the tank? No. Do I trust my eyes ability to recognize color and the presence or absence of algae? Yes!
 
Ron Reefman said:
srusso,

Companies make lumen meters and PAR meters. They aren't cheap, but they are made and sell ( I have a PAR meter). So a meter that reads the color spectrum of the bulb is going to be too expensive?

Reading spectral information is a world different from measuring brightness

And if the manufactures test their bulbs, why don't they provide how many hours they can be run before the spectrum changes?

because it changes from application to application and even from bulb to bulb. It's like trying to tell someone how many miles they will get out of a new car. It's going to depend on how they drive and how they treat the car. There's just too many variables involved.

If I'm a bulb manufacturer, and I make a bulb that lasts longer than my competitors, wouldn't I make that a selling point?

You wouldn't be able to guarantee it. If you did you would quickly go out of business because you can't possibly disclaim every little thing that could shorten the life of a bulb.


But none of the manufacturers even address the issue of regular bulb replacement. And the time frame most reefers quote is anywhere from 6 months to a year, no matter what kind of bulb (except leds which last 10 years).

It varies from bulb to bulb, fixture to fixture, and application to application. 6mos to a year is a "rule of thumb". An average if you will. Your actual mileage may vary.

Northreefer,

I had VHO bulbs over my old 75g system for 18 months, and like you, didn't have any issues either. In fact the PAR readings on the 18 month old bulbs was almost exactly the same as the new bulbs I got to replace them.

Individual results will vary. We're not talking about an exact science. The lifetime of a set of tubes depends on a huge number of things, from on - off cycles, to the particular ballast that is driving them, to the amount of line noise coming into them.

That is part of why I want to understand this issue. The MH bulbs over my current 180g have been running for a year now and I have no issues now. Coral growth is as good as it has ever been and no algae (and I haven't run GFO in the last 6+ months).
That's good. If you start having algae problems that you can't find the source of, lights is one thing you can try. Otherwise, if there's no problem then there's no worry.
Click to expand...

Again, this varies over so many things.

Do old lights ALWAYS cause an algae bloom? No, of course not. That would be a ridiculous assertion. So many other things go into growing algae.

Does a lower temp color spectrum favor algae growth? Yes. So all other things being equal, the algae will be happier with the older lights that have experienced significant phosphor degradation.

Do new lights ALWAYS prevent algae. Again, of course not. That would be silly. Given a bunch of nutrients, I can grow algae in just about any light.

Will it grow as well or as fast? That is again going to depend on a whole bunch of things.


There are so many variables in the algae equation, and lighting is just one of them.
 
Ron Reefman said:
disc1,

I apologize for my post sounding "hostile", that wasn't my intent. I just find it frustrating that I read, or hear hobbists say, "Change your bulbs when they get to be XXX old." And if you ask why, the answer is, "Old bulbs can cause algae." If this really is the case, why hasn't somebody come up with a tool that I can test my lights with which will tell me when I should change my bulbs rather than an arbitrary time frame?

Because that just isn't practical. It would depend on so many different things. Remember, most of the advise you get around the forum is an average of all experience. None of the "rules" are absolute, and nobody knows your individual tank like you do

And over a big system, bulbs can be a very expensive, reocurring cost. I have 5MH and 6 fluorescent bulbs over my 2 tanks.

Big tanks can get expensive.

I appreciate the links you've provided and I will read and try to understand a science that I admit is a little over my head (not that I'm stupid, I've just never needed to understand this much science about light before :headwallblue:). I did read the link about PAR and found it very informative and understandable.

I tried to be careful in my use of the word ignorant (simply defined as not having learned something yet) and hoped it wouldn't be confused with stupid (incapable of learning). I fear that a thorough discussion would go over the heads of most rather quickly.


One of your comments strikes to the heart of the matter. You wrote, “It's also not hard to find out what happens to the spectrum of different lighting options as they age.” I briefly looked at all the links you provided (I admit I haven’t read them all and will need to read them more than once or twice), but I didn’t see anything that relates to the comment about what happens to the spectrum of bulbs as they age. And I guess more importantly, how can I test for that change?

Those are the more scientific looking ones about phosphor degradation. It is a very large topic with many different viewpoints. More than I want to get real deep into other than to understand that those phosphors are what takes the narrow spectrum produced by the mercury in the lamp and turns it into whatever spectrum we desire from our light.

Your first post… sent me to Google… which was cute… OK, funny,
but it also gave me a site that provided this info: ”Algae colonies, in general, grows at wavelengths between 660 to 700 nanometers.

That is the very reddest of the red part of the spectrum

Cyanobacteria is known to grow at much shorter wavelengths between 530-620 nanometers.

That's the yellow / orange region

Old bulbs and lamps will produce the lower wavelengths that will foster Cyanobacteria blooms.”

So actinic bulbs fall pretty close to this 530-700nm

That is only the red and yellow light. Actinics are blue. I'm not sure where that number came from, but it can't be right.

range, some are even in it. Does that mean that some actinic bulbs are good for algae growth even when they are new? A 10K bulb is equal to 290nm

That is invisible UV light, it can't be right either. 290nm will burn your skin. It should be a range.

which is way below the 530-700nm algae producing light range. That makes 14K (210nm) and 20K (145nm) bulbs even further from the ‘algae growth” numbers. As they age, do they really change that much? I’m not trying to be sarcastic or funny, I’m trying to understand. I assume I’m missing something? Can you help?

Again, those numbers are UV light. That can't be right. There may be an intensity peak there, but it doesn't represent everything that comes out of the bulb.

Ron
Click to expand...

I think you have the bulb spectrum thing a little confused. The numbers that you give don't make sense as single numbers. Think of color temperature as a curve, not unlike a bell curve, with a peak at some number. Most real-world bulbs have several peaks. As the spectrum falls off, you still get every one of those wavelengths, the bottom of the curve doesn't move. What moves is the peak of the curve. That shifts towards the red, so that there is more red in the overall spectrum. Those same wavelengths were there before, but not as intense.

So any of these bulbs produce wavelengths across the entire spectrum. It's the relative intensities that we need to look at.
 
Last edited:
http://reefkeeping.com/issues/2007-04/ac/index.php

This does NOT measure or give a quantitative affirmation on the BS meter of the premise of algae blooms or not.

And nor will this post critique someone's posting style and then just flood the thread will tail chasing links.

But, this study with the lighting guru Sanjay Joshi's name on it indicates how to measure a bulbs useful life. The corals which are the desirable focus for reef lighting will gain an acclimation to the aging output of the metal halide in their trial.

While some bulbs such as VHO or PC's are rumored to promote bad algae blooms the bottom line is that if there's little to no nutrient present and plenty of current then 2 of the 3 components that fuel blooms have been eliminated.
So those couple variables I will say have more bearing on the likelihood of algae bloom promotion over aged bulbs.

But if I wanted to know the exact answer to the riddle a well thought out letter to Sanjay in the hope of a reply would be my primary source. And the second would be to conduct my own tests. The latter would be my last choice since unlike Sanjay it's doubtful we have the equipment to pull it off. And to read through all kinds of linked information without an actual trial is all just a lot of speculation in my humble.

Good Luck on your quest.
 
http://www.americanaquariumproducts...._Lighting.html

This was an incredible article! It had tons of information and it was presented in a way that most people could understand it... well, most of it anyway. disc1, I really want to thank you for finding and sharing this article. Seriously, I learned so much about light that I didn't understand before. I'm even going to ask Carl Strohmeyer, the author of the article, to clarify and expand on the statement he made that I quoted below.

So in a HUGE article (only 1 page on the website, but it had a really long scroll bar) that covered a vast number of light related topics, this was all it had to say about old lights:

Changing bulbs:

With the exception of LED, most aquarium bulbs go through what is called a half life whereby they are at 50% output. This generally happens around 6 to 9 months in time with normal usage however with lower usage (say 8-10 hours per day) this can be stretched to 12 months.

It says 'most' bulbs... I think that implies 'not all' bulbs? So what are the exceptions? And it says nothing about a color shift with age. It says the bulb "output" is reduced to 50%. Output measured in what?

As I said above, thanks for the help with learning more about this and I'm composing a letter/email to send asking Carl Strohmeyer
for more information.

Ron
 
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