# [Wet Thumb Forum]-blue green algae hell



## pankis (Oct 27, 2004)

I have a 75 gallon plant tank that I've had running for about five years now. It's a well lit tank, stocked normally (discus, tetras, a couple clown loaches, a few ottos), magnum 350 canister filter . . .

Anyway, about two years ago I was blessed by an emergence of blue green algae. Slime everywhere, all over my plants, the gravel, even the sides of the tank. Following instructions on various fish boards, I dosed with a maximum dose of maracyn for five days, wherupon the bacteria disappeared. Three weeks later I spotted a small piece of it on a plant, four weeks later, it was back in full force. So I tried a blackout. That did nothing. I tried lowering my lights to two hours a day for a few weeks. Nothing but sad plants. I tried upping my water change schedule, removing 50% every couple of days. It would all come back one or two days later. So then I didn't feed my fish for a week. No luck. I completely drained the tank, rinsed everything out, moved to another location, set it all back up - all the bacteria was back in a few weeks. I've dosed three or four times with maracyn now, each time it removes the bacteria for a few weeks, then it comes back in full force. 

I'm desperate. It's definitely affecting my bottom feeders (who have to sit in it all day), and my plants look awful, totally suffocated. Not to mention the annoyance of having to remove it all the time. What do I do? Is there another antibiotic that is more intense and will kill it? I'm about to rid myself completely of lights and live plants out of frustration. I'm not exactly a beginner, I've kept discus and many other fish for five years, and up until this algae problem, my plants looked great. How do I get rid of the cyanobacteria? Help!


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## pankis (Oct 27, 2004)

I have a 75 gallon plant tank that I've had running for about five years now. It's a well lit tank, stocked normally (discus, tetras, a couple clown loaches, a few ottos), magnum 350 canister filter . . .

Anyway, about two years ago I was blessed by an emergence of blue green algae. Slime everywhere, all over my plants, the gravel, even the sides of the tank. Following instructions on various fish boards, I dosed with a maximum dose of maracyn for five days, wherupon the bacteria disappeared. Three weeks later I spotted a small piece of it on a plant, four weeks later, it was back in full force. So I tried a blackout. That did nothing. I tried lowering my lights to two hours a day for a few weeks. Nothing but sad plants. I tried upping my water change schedule, removing 50% every couple of days. It would all come back one or two days later. So then I didn't feed my fish for a week. No luck. I completely drained the tank, rinsed everything out, moved to another location, set it all back up - all the bacteria was back in a few weeks. I've dosed three or four times with maracyn now, each time it removes the bacteria for a few weeks, then it comes back in full force. 

I'm desperate. It's definitely affecting my bottom feeders (who have to sit in it all day), and my plants look awful, totally suffocated. Not to mention the annoyance of having to remove it all the time. What do I do? Is there another antibiotic that is more intense and will kill it? I'm about to rid myself completely of lights and live plants out of frustration. I'm not exactly a beginner, I've kept discus and many other fish for five years, and up until this algae problem, my plants looked great. How do I get rid of the cyanobacteria? Help!


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## Roger Miller (Jun 19, 2004)

You seem to have a consistent problem. It isn't that hard to keep blue green algae from becoming a problem. If you have a consistent problem then there is some feature in your setup and/or maintenance that creates conditions favorable for the blue green algae. You need to identify that feature and change it.

I would love to help, but your description to this point is very short on details. If you can describe your tank conditions and maintenance more precisely then we might be able to help. 


Roger Miller


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## TopDuck (Nov 1, 2004)

Re: Blue-green algae (cyanobacteria) hell

Hi,

I know this experience!

I eventually solved it by simultaneously decreasing:

i) pH to 7.2 or lower, by decrease of kH to 2-4 and by increase of CO2. 
ii) nitrate to < 5 mg/L, by use of anaerobic filter i.e. dropwise filter in which nitrate is converted into nitrogen gas.
iii) phosphates by use of phosphate absorbing zeolite (e.g. JBL PhosEx, best used in improvised reduced flow cannister).
iv) Fish food - absolutely do not overfeed when you have cyanobacteria.
v) I also use reverse osmosis water i.e. nitrate and phosphate free, hardened by adding a small amount of of minerals (AquaDur). Actually I think that once the the nitrate ane phosphate have been decreased so that the cyanobacteria have disappeared, that this point is no longer necessary.
vi) Daylight in aquarium.

These are all low maintenance options, so that I now have the pleasure of watching the water quality increase continuously in a densely populated 400 L aquarium, whilst doing only the weekly water change of 10%.

Best regards,

TopDuck


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## Roger Miller (Jun 19, 2004)

TopDuck

I don't dispute that those measures may help get rid of a cyanobacteria bloom. I do think that some of those methods will work much better in a non-planted tank than in a planted tank. Unless you have a very fertile and stable substrate the plants will depend on nutrients in the water for their own health and growth. If you strip the nutrients (including nitrogen and phosphorus) out of the water then the plants will languish and eventually die.


Roger Miller


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## pankis (Oct 27, 2004)

Some details:

75 gallon tank, fully established for 5 years.

I do a 40% water change once a week, vaccuming the open gravel in the process.

I don't have much money, so I can't really afford all the fancy testing stuff, but I did take the water into my LFS a few weeks ago - they said the nitrates were so low they didn't even register on the test.

pH: fluctuates between 7.5 and 7.8. Comes out of the tap at 7.8. Definitely not ideal for discus, so I used to inject CO2 to lower it, which also helped the plants grow, but didn't seem to do much to the BGA. My discus seems happy either way, I've had him for 5 years.

I feed once a day, some flakes and a few sinking pellets for the bottom feeders.

Fish load: 1 Discus, 2 Angelfish, 4 3" Clown Loaches, 2 Ottos, 2 Corys, 1 rubbernose pleco, a couple of misc. Tetras, and 9 Rasboras.

Plants: Anubias, Java Fern, Gian Hygro, and Wendti Cryp (sp?)

Lights: three 48" flourescent tubes, used to be four, but I took one out in an effort to eliminate the BGA. Plants seem to do ok with just the three. They're on for 8 hours a day, on a timer.

Filtration: a Magnum 350 canister filter. Also a reverse flow undergravel filter run by two powerheads.

Substrate: normal (natural looking) 2-3 millimeter aquarium gravel, 2-3 inches deep.

Fertilization: I've tried lots of things. Tablets, general flourish liquid, just relying on fish, iron spikes, etc. Currently nothing - haven't fertilized it in about three months due to lack of growth anyway due to all of the BGA.

Here's a small picture of the tank, taken right after a manual removal of all my BGA and a large water change:










Thank you for your help, and let me know what other details I can provide!


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## pankis (Oct 27, 2004)

Oh yeah, and if it helps, I've never had problems with other types of algae. I've seen some normal green fuzzy stuff grow on rocks and stuff, and some black algae on corners of leaves, but nothing out of the ordinary or out of control.


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## Roger Miller (Jun 19, 2004)

First, I don't think that keeping live plants is causing your problem, so getting rid of them will probably not help. It may hurt.

I'm not surprised that the tank has never had much of an algae problem. I have always found that cyanophytes typically grow best under conditions where algae doesn't grow well. In fact, one "cure" for BGA that a few people have found is to trigger a green water outbreak. When the green water outbreak is over the cyanophytes are usually history. For a while, anyway.

You have a consistent problem, and fixing that problem requires that you change something in your tank that favors blue green algae. The things that you have changed so far are obviously not the solution, so the answer has to be in doing things that you haven't done before.

I've always found that BGA grows well in dim light -- better in fact then most algae and almost any plant. Dim light seems to favor the growth of BGA. Certainly the worst BGA problems I ever had were under dim light. Bright light isn't necessarily a silver bullet, but it seems to help.

In non-planted tanks BGA is often regarded as a sign of pollution, and there is data to support that. It sounds like the approach you have been using is aimed at reducing "pollution" in one form or another. In planted tanks and in nature BGA often dominates where nutrient levels are too low to support healthy growth of plants and most algae. In that case, reducing or stopping fertilizers, using large water changes, minimizing feedings and so on may actually make the conditions worse, not better.

A lot of other tweaks have worked for different people at different times. Changing the circulation pattern for instance has helped some people. You can try a lot of things to change conditions in your tank. The one thing that is really certain is that you have to make changes somewhere.

What I would do is:

Remove all visible BGA. Probably at this point there is no point to repeating the Maracyn dose. You may very well have developed a resistant strain.

Put that 4th light back on the tank. With it you have about two watts/gallon, which should get you better plant growth. Look into upgrading your lights to get 3 watts/gallon.

Return to fertilizing your plants. In particular, you need to make sure that your tank is getting enough nitrogen, potassium and phosphorus as well as trace nutrients. When your LFS told you that your nitrate reading was off scale low that was bad news. The nutreint concentrations don't have to be high, but they need to be there. Giving your plants an adequate nutrient supply is the only way that the plants can stay healthy. Without nutrients there is no chance that they can stay in good health, BGA or no BGA. The increased nutrient levels should favor plant and algae growth over BGA growth. You may get some more algaes then you're used to, but that can be controlled.

Consider going back to using CO2 -- but don't do this without also making sure that the fertilizers are adequate. At the light levels you are providing the CO2 probably isn't very important. With brighter light it becomes more important.

Reduce your water changes; there isn't anything necessarily wrong with 40% weekly water changes, but it does make it more difficult to maintain nutrient levels. 15-20% weekly water changes should be enough.

Look at anything else (filtration, for instance) that you have kept constant through the problems, and change it. I've always found that controlling BGA required that I change something in the tank, but often that "something" is a seemingly minor detail.

Finally there are at least two other things I've found that will kill BGA. I can't recommend you use either of them, but they have worked for me. First is copper sulfate (I think the product "Copper Safe" is a copper sulfate solution). Copper is an insideous poison. It can wipe out BGA, algae, snails and some parasites. It can also kill and maime fish. Other antibiotics may also work. I once added penicillin to a tank infested with BGA. As a side effect of the treatement the BGA disappeared.


Roger Miller


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## pankis (Oct 27, 2004)

What brands/types of fertilizer would you suggest using? Where should I buy it? What exactly should I do to use it correctly? 

Also, any tips on getting CO2 to have a consistent flow? I've got a pressurized chamber that I get filled at the local gas place - routed to a dial that I can turn to adjust the flow, then a tube that goes into the output of the canister filter. I had it running for awhile with good results, but stopped using it awhile back because one day my pH had dropped to 4.5 and all my fish were floating around. I did a quick water change and saved all of them, but it spooked me. 

Last question - is there some sort of yearly maintenence you're supposed to do on fish tanks? I've heard people say you should rip them down and start from scratch once a year, but that scares me as well - mine's been running for five years now.

Thanks for all your help.


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## imported_BSS (Apr 14, 2004)

If your pH crashed like that, you likely had a shortage of KH in your tank. I would suggest looking at www.rexgrigg.com to get one view of fertilization needs. I'd then suggest reading through some stuff on www.gregwatson.com where you can also get needed fertilizers at a pretty decent price.

As to the yearly maintenance question, it's not something I have any plans to do, but my 46g is only about 10 months old at this time.

Good luck,
Brian.


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## Roger Miller (Jun 19, 2004)

> quote:
> 
> Originally posted by pankis:
> What brands/types of fertilizer would you suggest using? Where should I buy it? What exactly should I do to use it correctly?


A good trace nutrient mix is probably your most basic need. There are several brands available. Some brands include potassium in the mix, and that is a good addition. I use Seachem's Flourish Comprehensive in my low-tech tanks, but there are other options, and a lot of places to by them, including pet store chains, your LFS and online sources.

Macro nutrient fertilizers provide nitrogen, potassium and phosphorus. Potassium nitrate (sold as stump remover) can be used to add nitrogen and potassium. Phosphorus can be added with Fleet brand enema, or with sodium biphosphate (sold as a pH buffer). You can also get macronutrient fertilizers made for aquarium used by at least three different companies (Kent, Seachem and Hagen).

This forum is full of advice on proper fertilizing. I would reduce my water change schedule before adding any macronutrient fertilizers. You should probably buy a nitrate test kit to help you figure out what your tank needs. Nitrate test kits are relatively inexpensive and more dependable than some other kits.



> quote:
> 
> Also, any tips on getting CO2 to have a consistent flow? I've got a pressurized chamber that I get filled at the local gas place - routed to a dial that I can turn to adjust the flow, then a tube that goes into the output of the canister filter. I had it running for awhile with good results, but stopped using it awhile back because one day my pH had dropped to 4.5 and all my fish were floating around. I did a quick water change and saved all of them, but it spooked me.


That sounds like a fairly standard set up, but with a problem. You might post to the hardware forum here. Describe the equipement you have and what happened. They can probably help. But going back to CO2 should not be one of the first things you do. Your lighting and your plant selection don't demand a lot of CO2.



> quote:
> 
> Last question - is there some sort of yearly maintenence you're supposed to do on fish tanks? I've heard people say you should rip them down and start from scratch once a year, but that scares me as well - mine's been running for five years now.


Absolutely not! I've had low-tech tanks running continuously for as much as 17 years without any tear-downs. As far as I'm concerned, if someone needs to take a tank down once/year to keep it healthy then they are doing something wrong.

Roger Miller


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## imported_shalu (Feb 13, 2004)

I used to have it in my 100 gallon discus tank. I got rid of it first with antibiotic(maracyn), which did not affect fish or plants, then I improved my maintanance and dosing. My bioload is extremely heavy so I increased my water change is 3x60% weekly. Increased CO2 to 30ppm, dose macro/trace nutrients regularly with each water change, have not seen a sign of BGA since.

I have a DIY CO2 reactor in my wet/dry sump, with a ph controller/solenoid. I can/have run my CO2 tank pressure to 0psi without worrying about ph crash caused by CO2 dumping. There is a lot of info on CO2 reactors on this site.


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## pankis (Oct 27, 2004)

So, interesting results. The blue green went away (mostly) for the first time in two years!

Here's what gets me . . . all I've done is reduce my water change schedule and add some more fertilizer. What a weird thing. I hope it continues to work.


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## Roger Miller (Jun 19, 2004)

I hope the trend holds up for you. You might also consider adding a few more plants to your tank. Tanks that are dominated by healthy plants have much fewer problems then other tanks. You should consider only those plants that grow well permanently submersed in fairly low light.


Roger Miller


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## pankis (Oct 27, 2004)

I've had good results with anubias and java fern thus far - they seem really hardy. Any other plants like those that you'd suggest?

I had giant hygro in there, and it grew a TON in just a month, to the point that I had three different plants growing from the original one, but eventually they all stopped growing altogether and lost all its leaves and died. Any reason for that? I had the same thing happen with some normal green hygro. Is that a fertilization issue?


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## Roger Miller (Jun 19, 2004)

Hygrophilas (giant and otherwise) can grow in moderate light without extra CO2. When they don't nutrients are a likely problem.

A lot of plants will grow slowly but dependably in moderate light without CO2. All of them require added potassium, iron and trace elements, none of which is really provided in sufficient quantities by water changes, fish food or gravel substrates -- no matter how mature they get.

I've been getting good growth from Bacopa caroliniana under 1.75 watts/gallon without CO2. Sagittaria subulata is also growing well under those conditions. Many dark-colored crypts are perfectly happy (though slow-growing) under the same conditions. For a showier plant you might try a nymphaea (water lily) variety. Those are heavy feeders and may require trimming to keep them submersed. 


Roger Miller


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