# can't figure this green algae out...



## dwl0222 (Mar 6, 2011)

Hi, so I've had my 75 gallon up for well over a year. About a month ago I noticed green algae growing on the sand. Now about two weeks ago, I went in a new direction with my fish and got a red devil (3-4 inches). When I got the devil I switched to natural river gravel. Today I just noticed spots of very bright green algae. I don't know what's causing it. I do 40-50% water changes. My lights are just the standard fluorescent light and are on for about 8 hrs daily. I tested my water tonight and nitrite, nitrate and ammonia look good. So can any of you help me before this gets out of control?


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## DJRansome (Oct 29, 2005)

Blue-green slimy algae? Your nitrate is too low. Things seem to work better when it's between 10ppm and 20ppm. You would only need 8 hours of lights if your tank is planted...is it?


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## dwl0222 (Mar 6, 2011)

No it's not planted. Seems more of almost a neon green kind of. I did read somewhere that algae benefits from constant light as in 8 straight hours much more than it does if you spread out the lighting...So what if I do 4hrs on, 2hrs off, then 4 on again? How do I go about having "some" nitrates, but not to much?


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## The Cichlid Guy (Oct 18, 2014)

I run my lights 4 on, 4 off, 4 on, and it has helped cut way back on algae.

Too leave more nitrate, just slightly reduce the size of your water change.


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## BC in SK (Aug 11, 2012)

DJRansome said:


> Blue-green slimy algae? Your nitrate is too low. Things seem to work better when it's between 10ppm and 20ppm.


Levels of Nitrogen may favour one type of algae over another just as higher levels of Nitrogen generally favour plants over algae. But low or high levels of Nitrogen do not "cause" algae. 
And the low levels of nitrate may be the result of the algae using up ammonia or nitrate.
Generally, the lower the nitrate, the better the water quality is for the fish......so don't go trying to raise the level of nitrate by doing less water change on the mistaken notion that a higher level of nitrate is somehow going to get rid of algae :roll: 
IMO, choices are 2-fold. Cut down on the amount of light. While it may not eliminate the algae, it will slow it's growth down. 
#2. Consider getting some type of algae eater. Common pleco, CAE, or BN pleco. All will have there pluses and minuses in a 75 gal. with an RD/midas.

If you have sufficient light in a non planted aquarium that has been set up for some time..... generally there is probably something wrong if you are unable to grow any algae!


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## dwl0222 (Mar 6, 2011)

BC in SK said:


> IMO, choices are 2-fold. Cut down on the amount of light. While it may not eliminate the algae, it will slow it's growth down.
> #2. Consider getting some type of algae eater. Common pleco, CAE, or BN pleco. All will have there pluses and minuses in a 75 gal. with an RD/midas.
> 
> If you have sufficient light in a non planted aquarium that has been set up for some time..... generally there is probably something wrong if you are unable to grow any algae!


Thank you for your help! So if I read what you said correctly, the fact that I have algae growing is actually a good thing because it means my water is


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## dwl0222 (Mar 6, 2011)

Sorry, I hit the submit button by accident...So according to what you said, algae growth actually means my water quality is at an ideal spot for my fish? I had thought about algae eaters but wasn't sure what direction to go. I thought that a common might get to big along with a devil in a 75. Thought maybe a BN isn't "tough" enough to be with a devil. Not really familiar with CAE, I'll have ti look into them. Also, do I not need to worry about added bio load since I do fairly large weekly water changes? What direction would you recommend? I have had both common and BN in the past so I'm comfortable with either one, just want to make the right decision. Thanks again!


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## BC in SK (Aug 11, 2012)

My preference would be for a common pleco. Much better able to deal with the aggression of large cichlids. Also there armoured, so difficult to injure. Bear in mind that a lot more attention is directed towards a bottom feeder, when it is the only other inhabitant; not like a community tank where it maybe largely ignored and cichlid's generally focus on other cichlids. At a younger size, your RD/midas maybe more tolerant of it, but as it grows older become more aggressive towards it. 
I've housed common pleco with my dovii X festae hybrid for over 6 years now. Had him in a 75 gal. for along time but moved them into a 125 almost 2 years ago. As time went on he became more and more aggressive to the pleco. I added another large (10") pleco from another tank, and now with the 2 of them in there, it's much better. There out and about now; not getting attacked and bitten so much. Having had many RD/midas in the past, I would say my dovii X festae hybrid is a MUCH more aggressive fish. If a pleco can live with that as it's lone tankmate, I think it stands pretty good chance with RD/midas !


dwl0222 said:


> Thought maybe a BN isn't "tough" enough to be with a devil.


Sometimes they aren't. If it has to hide all the time, then it is not doing well enough. There a much smaller fish and you may need a few of them to eat the same amount of algae that a common is able to eat. Having a few might help things out so that your RD/midas does not single out it's only tankmate. 


dwl0222 said:


> Not really familiar with CAE, I'll have ti look into them.


Problem with a CAE is going to be finding one that is large enough and then growing it fast enough that it does not end up being swallowed whole, by the RD/midas. Unless your CAE is over 6", it has insufficient girth to prevent it being swallowed by a large midas/RD. have had many swallowed whole in the past by RD/midas and JD....even with a tail sticking out of their mouth for over a day. There skinny, so even if they are fairly long, they can still be swallowed whole!


dwl0222 said:


> Also, do I not need to worry about added bio load since I do fairly large weekly water changes?


If the tankmates are eating primarily algae, then it's really not adding to the bioload. What there eating is already in the system!
That is, unless you are feeding the tank significantly more....it depends on what you feed the tank!
Of course it is still good to do large weekly water changes, regardless of what you deide to do.

There is a third option that I failed to mention. Fast growing plants like elodea or hornworth could out compete the algae. A lot of times floating plants are not bothered so much by CA. Had some success with both these plants in the past, with large CA. IME, hornworth is prone to boom and bust; grows like crazy to begin with, then starts to die off and then get attacked by algae. I end up having to throw it out; have had much longer term success with elodea. But it's hit and miss with CA and certain plants; with nothing else to do your fish might spend too much time biting it up. No real way to predict with out actually trying it.


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## dwl0222 (Mar 6, 2011)

Wow thanks so much for your help! I also would prefer a common but don't know what I would do with it when it gets too big haha. But I also don't want to get BN and have them get abused. So I guys it comes down to if I want to get 1 common or maybe 3 BN to disperse aggression. You said you would prefer the common so maybe I'll go that route if I can find a nice 6 or so inch one. You think that's a good size to aim for? I do have 2 giant danios in there as dithers, so maybe they will help keep some attention away. Id like to get a couple more danios but I dunno that I can find full sized ones...


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## DJRansome (Oct 29, 2005)

Chiming in. Zero nitrates are good for the fish but blue-green algae is usually not. I've also gotten blue-green algae in a planted tank when a fast growing plant (vallisneria in my case) sucked up all the nitrate...then started to die off giving the blue-green algae an opportunity.

BC in SK...what causes blue-green algae (bacteria) in a tank with no nitrates and no plant die-off?


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## dwl0222 (Mar 6, 2011)

Here is a picture of the algae on my substrate. It's not much yet but Im hoping to stop it before it gets too bad. DJRansome, is this the blue green algae you speak of?


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## DJRansome (Oct 29, 2005)

I can hardly see it...hard to tell, that's very little algae. I'd probably wait a bit to see if it gets better or worse before taking any action other than reducing the lights. I think you are doing a fine job! :thumb:


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## BC in SK (Aug 11, 2012)

DJRansome said:


> BC in SK...what causes blue-green algae (bacteria) in a tank with no nitrates and no plant die-off?


If the plants continue to grow and do well....you would not expect to see blue-green algae starting to take hold. The plants are already there and have a strong foothold and the "algae" not being yet established have the disadvantage. As long as there are fish in the tank there is a source of Nitrogen (as well as other nutrients). It comes from the food we put in the tank. Zero nitrates doesn't mean there is no source of Nitrogen....just that all the ammonia and nitrate is being utilized. With very low nitrates, some of the plants are probably doing well, while others are starving and have probably stopped growing/thriving. With some plants no longer growing, nor thriving as they once did, it's going to provide an opportunity for some kind of "algae'' to start up.
Some types of blue-green algae can use atmospheric Nitrogen. In most aquariums, Nitrogen is seldom a limiting nutrient, but if it is, it's one big advantage to some types of blue-green algae.


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## dwl0222 (Mar 6, 2011)

Yeah I know...it's not much but it showed up overnight it seems and there is more like that throughout the tank. Its not quite as easy to see in the picture as in person. Like I said just wanted to get some thoughts before it got out of control rather than waiting till after...i may still get a pleco of some sort as a preventative measure as I was considering that anyway. Thank you both for your help, I do appreciate it. I'll keep an eye on it, keep up my water changes and lower my lighting time to see if that helps.


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## BC in SK (Aug 11, 2012)

DJRansome said:


> I'd probably wait a bit to see if it gets better or worse before taking any action other than reducing the lights.


I agree. Try reducing the amount of light, and see if that is enough to keep it from growing "out of control".


dwl0222 said:


>


IMO, looks to be blue green algae, though couldn't say that for sure as there really isn't too much there. 
One thing about blue green algae is that it does not attach to surfaces all that well,so if it takes off and starts to grow rapidly, a good part of it can be siphoned away with a water change.


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## dwl0222 (Mar 6, 2011)

Ok great, that's reassuring that it doesn't attach very well. Next weekend when I do my weekly water change I'll be sure to try and siphon that stuff loose. You think it's worth still getting a pleco? Being that I have a small red devil, I think it's now or never as if I wait until it's too big I'll be asking for trouble.


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## Loume (Dec 27, 2014)

dwl, i noticed you said, "My lights are just the standard fluorescent light" . Does that mean like the cheap ones you would buy at home depot? If so, don't, most of those bulbs put out a spectrum of light that may promote growth of cyanobacteria or other nuisance algae. I'd stick to high quality bulbs made for the aquarium.

Also make sure your tank has good circulation. If it is green/blue cyanobacteria, it loves low oxygen conditions. Is it only growing on the gravel so far?


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## BC in SK (Aug 11, 2012)

I think the question "What causes algae?" is often based on the notion that algae isn't supposed to be there and something that is wrong in the tank can be changed in order to eliminate it.
Basically water + light + nutrients= algae. I think a better question is what is going to stop it? There can be an insufficient amount of light. Higher plant forms can out compete it. Some types of algae eating fish can keep it in check. Pretty much impossible to starve out algae in an aquarium (other then maybe with an algae scrubber :-? , by growing it so well in one place it does not grow else where)
Algae gets it's start coming from the air, water out of the tap, and from other aquariums when we buy fish (maybe from the fish's waste if they ate some). What ever the conditions of your tank, it is likely favourable for some type of algae. Algae comes from algae. It just needs a start, and it can grow from there.



Loume said:


> dwl, i noticed you said, "My lights are just the standard fluorescent light" . Does that mean like the cheap ones you would buy at home depot? If so, don't, most of those bulbs put out a spectrum of light that may promote growth of cyanobacteria or other nuisance algae. I'd stick to high quality bulbs made for the aquarium.


Bulbs vary considerably in terms of the spectrum they produce, regardless of where you purchase them. Paying more for bulbs isn't going to stop most algae. If someone can post a link on any studies showing the growth of cyanobacteria under different bulbs, or even some circumstantial evidence claimed by aquarists, I'd like to see the evidence. Bear in mind as well, that cyanobacteria is thousands of different species and a bacterial bloom may have many species involved. Many algae will thrive under lower light conditions than many plants would do well under. On top of that, like red algae, some types of cyanobacteria can utilize the green spectrum (a part of the light spectrum that plants do not use).


Loume said:


> Also make sure your tank has good circulation. If it is green/blue cyanobacteria, it loves low oxygen conditions. Is it only growing on the gravel so far?


Increasing circulation might be worth a try, though I wouldn't put too much faith in it. Even if the cyanobacteria thrive under low oxygen conditions, doesn't mean they wont' thrive under high oxygen conditions.
The main problem I see with cyanobacteria is that it can take off and grow ridiculously fast, covering everything...then it starts to die off quickly contributing to poor water quality. Some are toxic, some are not (eg. spirulina). I would suspect most in the aquarium are not so toxic. I've had a few bouts of blue green algae over the last 4 years.....they were cleaned up with in 2 days by either a common pleco or a CAE. If they really were toxic, I would think these fish would have died eating the amounts of it they did! I'm sure cyanobacteria lurks ready to take hold of my tanks when conditions are favourable to it, but the algae eaters prevent it from ever being visible.


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## dwl0222 (Mar 6, 2011)

Loume said:


> dwl, i noticed you said, "My lights are just the standard fluorescent light" . Does that mean like the cheap ones you would buy at home depot? If so, don't, most of those bulbs put out a spectrum of light that may promote growth of cyanobacteria or other nuisance algae. I'd stick to high quality bulbs made for the aquarium.
> 
> Also make sure your tank has good circulation. If it is green/blue cyanobacteria, it loves low oxygen conditions. Is it only growing on the gravel so far?


Hi Loume, sorry I should have been more specific...what I meant was it's a standard fluorescent bulb that came with the aquarium fixture. So it is a bulb meant for aquariums. Also, I do have good circulation...have an ac110 and fluval 406, as well as two hydor powerheads and a marineland powerhead. I usually rotate which one or two I have on at a time, or sometimes all 3 at once...


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## cbsmith (Feb 17, 2015)

Bulbs will also change light spectrum as they age which can cause unwanted algae growth. This is a bigger issue in planted tanks and salt water reef tanks where the bulbs need to be changed at least once every year. If your bulbs are older this could be contributing to the algae growth as well.


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## dwl0222 (Mar 6, 2011)

I think the fixture and bulb itself is the same age as the tank....probably about 2-2.5 years. But I've literally only used it for about a total of 3 weeks, I have had a marineland led on there for the most part. But once I got the red devil I decided to give the old fluorescent a shot again and I really loved how it really made the Orange color pop...


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## BC in SK (Aug 11, 2012)

cbsmith said:


> Bulbs will also change light spectrum as they age which can cause unwanted algae growth. This is a bigger issue in planted tanks and salt water reef tanks where the bulbs need to be changed at least once every year. If your bulbs are older this could be contributing to the algae growth as well.


That's in a planted tank ( or a saltwater tank with live coral). Aged bulbs mean less light for the plant. When the plants are not thriving because they are getting less light, it allows algae the opportunity to take hold. When plants stop growing, there not taking up the nutrients. What ever are the limiting nutrients are, now become available to the algae. 
In an unplanted tank, aged bulbs will grow less algae. Even though algae generally need much less light to thrive then many aquatic plants, more light still equals better algae growth. Less light does not "cause" algae to grow. The very opposite. Unless you have plants to compete with the algae, change your old bulbs and you will definitely grow more algae :lol:


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## cbsmith (Feb 17, 2015)

Aged bulbs don't only lose output, the spectrum shifts to different wavelengths and that is the bigger problem. Algae can grow differently with different wavelength light so old bulbs can still cause algae to grow.


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## BC in SK (Aug 11, 2012)

cbsmith said:


> Aged bulbs don't only lose output, the spectrum shifts to different wavelengths and that is the bigger problem. Algae can grow differently with different wavelength light so old bulbs can still cause algae to grow.


Old bulbs can still grow algae.....but it's less light, so it's not going to grow as well as it does with a new bulb.


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## dwl0222 (Mar 6, 2011)

BC, if you were me would you still get a pleco? I know you said I don't have much algae and I agree. As I said, I just didn't want to wait until I did have allot to try and fix it. Also I don't want ti wait until my red devil is huge as he's already showing signs of getting aggressive. What direction would you go? Common, BN? if BN how many? And what size should I try for?


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## BC in SK (Aug 11, 2012)

dwl0222 said:


> BC, if you were me would you still get a pleco? What direction would you go?


Yes, I definitely would get a pleco. But that is how I keep all my tanks. With big cichlids, they can be messy eaters and do not eat small particles; a pleco will function as a bottom feeder as well, eating up uneaten food. Algae needs to be harvested before it dies off, rots and returns the nutrients back into the water column. 
I would get a common. There tough and sturdy and usually do well with large cichlids. 
IMO, it is preferable to have some kind of tankmate for a cichlid. 
Since you already have a couple giant danios, I would get a 4-5 more. They may not last forever (??) but they do have some chance of lasting for some time. I admit that I was rather surprised at how well they did with some of my cichlids....though I did lose my first 11 to predation in less then 2 years. There quick change in direction can make it a difficult target for large cichlids.


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## dwl0222 (Mar 6, 2011)

Great thanks! I'm gonna get out tomorrow and try to get them. Hopefully I can find some that are at least mid sized...As far as the pleco, does size matter as much? I mean I obviously won't get a tiny one, but I just don't know if I'll be able to find one 6 inches or so at any if my nearby lfs. I'll also pick up some sort of pvc cave or something that the pleco can retreat to and get away from the devil. I can't tell you how much I appreciate all your help, I promise I'm done with the "what would you do" questions


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## wortel87 (Apr 15, 2014)

Those are cyanobacteria.

you nitrates are 0 and thats probably causing it. Raise it to about 20. Clean the substrate really well each week and make sure you have enough flow across the bottom.


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## BC in SK (Aug 11, 2012)

wortel87 said:


> you nitrates are 0 and thats probably causing it.


If nitrate is truly zero, something is taking up all the Nitrogen. I think you have the causal relationship backwards. The algae is causing the low nitrates!
If the person had high nitrates there would an equal number of people claiming the high nitrates are "causing" it, and recommend a lot of water change as a way to eliminate it.
Different conditions in a tank might favour one kind of algae over another, but once it has a stong foothold, it's going to take off from there. 
As far as increasing flow, I've had cyano grow on power bars as well as on top of power heads.....it's definitely not adverse to growing in areas with high flow rate. 
I believe cyano is more common in a newly established tank. I also believe it is more common in tanks when plants or algae start to die off. 
We put different types of aquatic plants in a tank and conditions may favour one type of plant over another. We put algae in a tank by putting water and fish in it and conditions will favour one kind of algae over another.


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## wortel87 (Apr 15, 2014)

Redfield ratio helps. Flow helps. More oxygen helps. And realising this is not an algea also helps allot.


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## BC in SK (Aug 11, 2012)

wortel87 said:


> And realising this is not an algea also helps allot.


explain to me how or why it "helps"?
Brown, red, green...all as significantly different then "higher" plants as is autotrophic bacteria.


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