# Algae caused by insufficient lighting?



## Red_Rose (Mar 18, 2007)

I know that too much light can cause algae to appear in aquariums but is it possible for algae to show up when the lighting isn't the greatest? It's been about a year and a half since I replaced the bulbs(I use CFL bulbs) in my 10 gallon tank and I've noticed that I've been not only getting diatoms, which is the first time for that tank since I tore it down last year but the hair algae is growing more quickly now then it did before.

Could this be caused by the fact that the bulbs may not be producing the kind of light that they did when I first bought them? Would I see any improvements if I bought a new pair of bulbs whether they be the same watts or a bit higher? I've considered getting two 15 watt bulbs for the tank instead of two 10's that I normally use.

Thanks.


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## jlroar (Jun 21, 2007)

The best way I know to answer your question is imagine every month you place your typical black screen over your tank and next month add another layer and so on. Although light is getting through at this point it is not enough to keep the plants healthy.

Most lights should be replaced from 6 months to at most a year. When you do replace that bulb you will notice the light will be MUCH brighter so be prepared for other possible issues since the health of the plants may be slightly limited.

James


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## HeyPK (Jan 23, 2004)

One possible explanation is that the higher light causes your plants to take up more nutrients, leaving less for the algae, but the lower light decreases growth rate and nutrient uptake by your plants, but is still sufficient for the algae to grow. There are various species of hair algae, such as Cladophora and Oedogonium that do well at very low light levels.


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## Red_Rose (Mar 18, 2007)

Thanks everyone. 

jlroar,

What you said made a lot of sense and I can see how the older the bulbs, the less light the plants are getting because the intensity of the bulbs lessens definitely after a year.

HeyPK,

Your post also made a lot of sense too because it would explain why I'm getting more hair algae then when the bulbs were no where near a year old.

From now on, I'll replace the bulbs at the one year mark to prevent any of this from happening again. I'll go buy new ones later on today.


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## scooba (Oct 5, 2010)

wonder if the older bulbs put out light in a slightly different light spectrum than a new bulb would, possibly encouraging algae growth. i'm not speaking from experience (not having any really), maybe someone more knowledgeable can chime in.


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