Old Bulbs Cause Algae - Fact or Fiction??

[Dave]

So this is a topic I have been thinking about for a while, and frankly I do not understand how old bulbs can cause algae outbreaks.

So to be clear, this is really a question at its heart, and I am just putting down my thoughts.

First - even if this is true, I am fairly certain this is only a part of the equation. So fixing your bulbs would not resolve the underlying issues. e.g. phosphates, nitrates....

Second - It seems to me with all of the assorted bulbs out there at different Kelvin levels, we have many bulbs that span wavelengths.

I have read that bulbs as they age fall into wavelengths ideal for algae growth.

If a specific kelvin bulb was much better, than I would anticipate this would be well known by now.

If the older bulbs are causing an issue, could intensity of light be the larger factor?

There are some out there that state old bulbs play very little factor in algae growth.

I can say from personal experience I have seen tanks with old bulbs that have little to no algae, and tanks with new bulbs where algae is their "bumper crop".

In conclusion, I have seen little in the way of true evidence that supports the "old bulb"/algae connection, and I am looking for input from others.

 

[JRWOHLER]

I think that it can be a piece to the puzzle. Power compacts seem to be the biggest culprits.

For me MH and to a lesser degree T5 I think par decline is most important.
For PC I think wavelength and algae blooms problems are most important.
T5 can change wavelength also but think par decline is more significant.

Certainly if you are running a tank with zero nutrients you can put a plant bulb over the tank and it won't matter nothing will grow....so as you stated it is all a piece of the puzzle.

For beginners, PC is often their first choice in lights due to cost, suddenly after 9 months start seeing an algae bloom, the diagnosis of old bulbs is probably fitting.

 

[Dave]

While your analysis may be correct, it would be useful to have some supporting scientific data.

This is the closest I could come.

http://en.phyco.org/wiki/Algal_Light_Requirements#Fluorescent_Lighting

 

[mnat]

What I have always been told is that when PC bulbs age they start to put out a more red spectrum which leads to the algae blooms. I don't know why this occurs but there seems to be a lot of ancedotal evidence of this occuring. As James stated, it is just part of the equation of an algae outbreak and has nothing do do with nitrates/phosphates.

 

[mikem]

Great topic Dave. I'm following along to see what else I can learn.

 

[rodclement]

good points and questions! I had issues with algae and changed my MH bulbs that were 8 months old and the algae went away but...I also changed flow in the tank so can't tell for sure what helped.

Rod

 

[GregW]

I have a 150 gallon Rubbermaid tank with a 12 month old 250w MH. This tank has been exploding with hair and bubble algae lately. There are two other tanks tied into the same system and they have no algae problems. I'm changing the bulb this week so I'll keep you posted.

 

[mfisher2112]

Great topic for discussion. Following along.

I'd have to agree that the algae needs to have the nutrients to survive in addition to the lighting.

My personal opinion would be that the "fouling" light spectrum would only serve to accelerate something that already has potential to begin with.

 

[mnat]

After doing a bit of research it seems as bulbs age, they lose intensity and move towards the red spectrum. On a planted aquarium forum people actually ran the bulbs until they burnt out because they were trying to grow plants. To kind of simply this, look at like a fire. For a fire to start you need a source (spark), fuel (something to burn) and oxygen. Algae needs light, nitrates, and phosphates to grow. Red light apprently makes alage grow quicker and faster and that is why we replace the bulbs to try and keep it down.

An article from Marine Depot:
http://kb.marinedepot.com/article.aspx?id=10857

 

[Dave]

Grow lights are frequently at 6500 kelvin.

There are many hobbyists who still use 6500 kelvin lamps on their tanks. Do they experience a higher than average occurrance of nuisance algae?

Do the higher kelvin lamps "age better" when it comes to this topic since they are at the other end of the spectrum?

The article I posted suggests the following:

Both green and brown algae use photosynthesize light most efficiently around 435nm and 675nm. However, red algae photosynthesize most efficiently using other wavelengths. Moreover, red algae use little or no light of 435nm and 675nm.

 

[9supratt4]

I posted this similar question on another site and the discussion had some great input. The following was one point:

"The idea that the wavelength (color) of the light under which a coral has grown can influence some characteristic of the coral is not new. Kinzie and later Schlacher both have probed specific hypotheses is this general area of coral research. Seminal studies by Kinzie assessed coral skeletal growth rates under the influence of blue, red, green, and white growth lights for both Montipora verrucosa and Pocillopora damicornis (Kinzie, 1984). They concluded that these corals grew fastest under blue light, followed closely by white light, then green light, and finally the slowest growth was observed under red light. They followed up this study by measuring photosynthesis rates of Montipora verrucosa under these same lighting conditions (Kinzie, 1987). Once again, the highest photosynthesis rates were achieved under blue light; slightly lower but similar rates were observed for corals grown under both white light and green light, followed distantly by photosynthesis rates under red light. More recently, Schlacher et al. examined growth rates of Acropora solitaryensis under 150W metal halide bulbs rated at 5.5K, 10K, 14K, and 20K color temperatures (Schlacher, 2007). After 3 months of grow-out, the overall growth rates under the different bulbs were quite distinct: 6.2 mg/day at 5.5K, 4.9 mg/day at 10K, 8.5 mg/day at 14K, and 10.9 mg/day at 20K. Thus, the bulbs delivering the highest proportion of blue light (20K and 14K) promoted the highest growth rates."

So basically we came to the conclusion that the old bulbs shifting in wavelength make it more of an ideal situation for algae growth.

 

[JRWOHLER]

I assume that since most bulbs don't output exactly one band of light but are more of an average range that as they age more and more light is produced in the red spectrum. Thus the whole "graph" if you will shifts to red.

 

[Dave]

So basically we came to the conclusion that the old bulbs shifting in wavelength make it more of an ideal situation for algae growth.

Can you help me understand how this was the conclusion?

 

[9supratt4]

The conclusion was as everyone is saying....The aging bulbs shift in spectrum out of the blue spectrum and more into the red. Hence making the lighting conditions ideal for nusiance algae growth.

 

[Dave]

There is a poster on RC who I found while looking into this that stated:

"old bulbs dont cause any problems, thats the biggest myth in the hobby. Even if the XM bulb is YEARS old at WORSE it becomes the equivalent of a low PAR 15k bulb. Flourescent bulbs color shift are so slow and gradual you wont even know it visually. the most significant thing that happens with old bulbs (flourescent and halides) are a loss of PAR and this causes ZERO problems. If your corals cant be maintained from the PAR reduction of several year old bulbs your lighting was inadequate to begin with. You arent maximizing your light potential (slow growth) and it may not look sharp but thats it. Light shift doesn't cause algae unless you have other enabling problems and fresh bulbs with higher PAR are likely going to make the condition worse. low PAR certaintly doesn't cause algae (it would actually do the opposite).

there are coral and frag tanks all over the place with high powered 10k halide bulbs (most of which have CCT true kelvin ratings in the 8000-9000 range) and 6500k bulbs with ZERO algae problems. there isn't going to be any spectrum shift thats going to promote algae any more than these. algae is the result of multiple variables (light, phosphates, nitrates, dissolved nutrients). a bulb 6 months past its prime isn't one thats going to change anything beyond slowed growth from the intensity reduction (which is gradually occuring from the day you put them in). with halides there are more changes in the first 3 months then there is with an old bulb getting older (new vs 3 months compared to 3 month old bulb vs a year old bulb) so if this were the case we'd need to change bulbs all the time. after the first 3 months shifts and par changes are painfully slow compared to what happens with a new bulb (if problems from spectral shifts caused problems within a matter of weeks as you suggest every tank with halides would have problems because anyone with them will tell you the first month or two of use is where all the visual spectral shift occurs. more times than not becoming signifcantly whiter/lower kelvin which is just the color shift that should theoretically promote increased algae growth)."

Who should I believe? Why?

 

[9supratt4]

Here's a response from someone I was talking to about this:

"Because you make lighting conditions more ideal for nuisance algae to grow doesn't mean you SHOULD have a noticeable outbreak in nuisance algae. that is mearly one variable required for nuisance algae. its not like new bulbs provide terrible conditions for nuisance algae to grow in.

the point is people aways point to changing old bulbs for algae problems as if this will cure and fix the problem. old bulbs and color shifting arent the problem even if they do make conditios more ideal. the focus should be the other variables. you can put 3yr old halides over my tank and I wont get or expect a nuisance algae outbreak. if color shift from old bulbs is the difference between excessive nuisance algae and acceptable then you are walking a fine line of either nitrate, phosphate or nutrients too close and need to focus there instead of light shift."

I think I'm not stating what the reality is. Lighting will not cause algae to grow by itself. There are many other factors that com einto play regarding algae growth. But if the conditions are a bit off and your bulbs old, then you make an ideal system for algae growth.

If your water conditions are "perfect," then the change in spectrum of a bulb probably will not cause algae growth. So I guess the final conclusion is that old bulbs do not cause it....but they are one of many contributing factors.

I think we will be in agreement there.

 

[Dave]

I am truly not in agreement or disagreement with anyone, beyond there being more factors than old bulbs.

It is commonly known that myths take on a life of their own, and this is definitely true in this hobby.

To the point, where it becomes commonly accepted knowledge, and we all just accept it as fact.

I am more than willing to accept old bulbs play a role in nuisance algae, but thus far I have not found any good evidence to support this claim.

 

[9supratt4]

I can give you my personal experience. For 6-10 months my tank NEVER grew any nusaince algae, even though my nitrates have always been elevated. Around the 11-13 month mark, with my water parameters the same as they've always been my tank started to show signs of nusiance algae.

I just replaced my bulbs a week ago...so if the algae begins to slow and stop then that is in my mind...proof itself.

 

[Jcurry@wesketch]

I just replaced my bulbs a week ago...so if the algae begins to slow and stop then that is in my mind...proof itself.

As long as you don't do any other maintenance and continue to feed the exact same amount and frequency as before this may be true. But most people don't just change their bulbs when algae starts to grow more vigorously. They usually do more maintenance and more frequently until the algae recedes.

 

[9supratt4]

I just replaced my bulbs a week ago...so if the algae begins to slow and stop then that is in my mind...proof itself.

As long as you don't do any other maintenance and continue to feed the exact same amount and frequency as before this may be true. But most people don't just change their bulbs when algae starts to grow more vigorously. They usually do more maintenance and more frequently until the algae recedes.

Nope not me LOL.

Everything is the same...all I did was change the bulbs. I haven't even added to my CUC.