# Will cyanobacteria go away when tank settles?



## Andrew Reynolds (24 Feb 2020)

Hi,

I have a Juwel Vision 180 aquarium that I've owned for quite a few years. Until recently I have been neglecting it with water changes only every 6 weeks or so, but the fish seemed happy and the small cryps and giant Vallisneria was growing alright with just the standard Juwel T5 lights. There was a bit of blck beard algae.

Then the lighting unit failed so I ordered a replacement which has two 19w LED lights, one 6500K and the other 9000k.

When the new light arrived I decided I was going to revive the tank and get it looking good again. I gave it a good clean. Set up the CO2 system that I had not used for years, bought new plants, put in 6 small siamese algae eaters to fight the BBA and also bought 10 Rummy Nose Tetras. The total fish count now is 6 congo tetra, 10 Rummy Nose Tetra, 4 Serpae Tetra, 2 Coolie Loaches and 1 Rainbow Garra and 1 ammo shrimp.

I have two Hydor Nano 900 power heads to increase circulation as the internal Juwel filter only cycles the tank 4 times an hour.

The substrate has been in for years and is some sort of volcanic type that was recommended for plant growth at the time. I have used easy life root sticks near the roots of Amazon Swords and a big Cryp. I have used Tropica Premium Nutrition as a liquid fertiliser which has instructions to does weekly but I know a lot of people dose liquid fertiliser daily. I have also been using Seachem Flourish Excel daily (3ml) to help combat the BBA. I have had the CO2 & lights on 8hrs a day with the CO2 starting and stopping an hour before the lights. I have just reduced this to 6 hrs to see if it will help.

The new setup has only been in place for about 10 days. The tank is looking good and I can see oxygen bubbles rising from the plants, but I am getting cyanobacteria on the gravel and foreground plant at the front of the tank. I have been trying to remove this manually every day but it comes back each day.

My question is will the plants eventually out compete the cyanobacteria so that it disappears if I do nothing but normal weekly water changes, or should I do a 3 day black out or treat with something like Easy Life Blue Exit. I have 3% Hydrogen Peroxide but am nervous of it killing my filter material?

Also, I am wondering about reducing my quantity of fish by getting rid of the Congo Tetra.

All opinions gladly received.


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## dw1305 (24 Feb 2020)

H all, 





Andrew Reynolds said:


> My question is will the plants eventually out compete the cyanobacteria so that it disappears if I do nothing but normal weekly water changes,


I'm not familiar with the media set-up in Juwel filters, but I'd be tempted to give the filter media a rinse, and swap out some of the sponge for a coarser sponge? If it has a floss "water polishing pad"? throw it away.

If you get a bit more oxygen flowing through the filter media you may find that the BGA (cyanobacteria) disappears of its own accord as the plants grow in fully. 

It might not help, but the problems with black-outs and chemical treatments is that they just <"sticking plasters" and "magic bullets">.

cheers Darrel


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## Witcher (24 Feb 2020)

In my opinion the main cause of cyano is the lack of flow and too much of Phosphorus in relation to Nitrogen - I observe cyano quite often since I started to add more PO4 while reducing amount of NO3 - high P increases the growth of the plants, and obviously increased plant mass reduces the water flow across the tank. Less flow means it's easier for cyano to form their colony and high flow destroys it. So I think the flow is absolutely crucial in combating them (plus either going up with NO3 or down with PO4).


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## Andrew Reynolds (24 Feb 2020)

Thanks for your replies. I have just taken the floss pad out and it was quite dirty and had only been there about a week. The filter flow definitely improved. The sponges have been rinsed in tank water recently but they are pretty old so I will get some new ones.

Would running an air stone at night when the CO2 is off help getting more oxygen in to the filter?


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## Kezzab (24 Feb 2020)

Witcher said:


> In my opinion the main cause of cyano is the lack of flow and too much of Phosphorus in relation to Nitrogen - I observe cyano quite often since I started to add more PO4 while reducing amount of NO3 - high P increases the growth of the plants, and obviously increased plant mass reduces the water flow across the tank. Less flow means it's easier for cyano to form their colony and high flow destroys it. So I think the flow is absolutely crucial in combating them (plus either going up with NO3 or down with PO4).


I hate cyano. In different scapes using same co2, dosing, light and filter i've had massive problems with it and no problems at all. When it has occurred i have tried more NO3 (a lot more), no impact. Water changes, no impact. Black out, temporary impact. Dosing with peroxide, temporary impact. Only thing that "worked" was UltraLife Blue-Green Slime Stain Remover - once it had been dosed a couple of times it stayed away. God knows what's in it - there's a load of marketing waffle on the back. 

Anyway, to the OP regards an air stone, yes that would help a bit in terms of oxygen.

K


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## alto (24 Feb 2020)

This seems a bit dubious but an easy addition that your plants will like
(Seachem Flourish Potassium is same “salt”)

https://cals.arizona.edu/azaqua/ista/ISTA8/MOSTAFAABDEL.pdf

I’d also try increased oxygen/flow 

Re Seachem Excel, add 5ml/37 litres with a weekly 50% water change, then daily dose 5ml/189 litres (I’d just add a capful daily, the slight overdose won’t affect fish etc)

Unless you have significant other biomedia in your filter, replacing the old sponges may affect your tank “cycle” especially as it’s just been rescaped/cleaned etc, so only do 1 at a time


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## Franks (12 Mar 2020)

I've beat Cyano having been through it twice and nearly giving up. It wiped out all my plants it got that bad. It was growing off the plants and all over the substrate. it killed all the plants to the point there was no point trying to save them as they were too badly damaged.

I beat it by over-dosing H2O2 on a daily basis before lights on. Two capfuls of food grade 6% (approx 30ml directly into the water column with the filter running. Fish are unaffected, and while the cyano doesn't appear to die immediately, it started to reduce after a week. After a month, it was all gone. I bought 2L it from eBay for around £12 delivered.

I know this was probably damaging the good bacteria in the filter, it is harbouring the cyanobacteria so you must decide on your next step. I believe this is the reason how it stays inside your eco-system and while usually prolific to return the next day if manually removed, if you choose to dose with the filter off to "save" your good bacteria, you're never going to kill of the cyano spores living inside your filter when you turn it back on. IMO, you're left with the option of replacing all your filter media and have no bacteria or dosing H2O2 with the filter running and harming your good bacteria. I chose the latter.

I've since changed my substrate, and restocked on plants. I blame the fact I got cyano through poor maintenance. I rarely cleaned my external filter - which was usually 3 or 4 times per year although i did 50% water changes once a week. In a planted tank, your filter gets clogged with plant matter much quicker and I think this rots down over the months and promotes cyano bacteria.


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## dw1305 (12 Mar 2020)

Hi all,





Franks said:


> In a planted tank, your filter gets clogged with plant matter much quicker and I think this rots down over the months and promotes cyano bacteria.


That is one of the reasons why I'm very keen on excluding all bulky organic matter from the filter. 

I just wish that they <"weren't called filters">.

cheers Darrel


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## jaypeecee (12 Mar 2020)

Witcher said:


> In my opinion the main cause of cyano is the lack of flow and too much of Phosphorus in relation to Nitrogen - I observe cyano quite often since I started to add more PO4 while reducing amount of NO3 - high P increases the growth of the plants, and obviously increased plant mass reduces the water flow across the tank. Less flow means it's easier for cyano to form their colony and high flow destroys it. So I think the flow is absolutely crucial in combating them (plus either going up with NO3 or down with PO4).



Hi @Witcher 

I have a scientific research article that should be of interest here. Will check it out and give more details tomorrow when I have a bit more time.

JPC


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## lazybones51 (12 Mar 2020)

I had a similar experience to @Kezzab. I bought UltraLife Blue-Green Slime Stain Remover as a last resort and now have a completely BGA free aquarium


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## jaypeecee (13 Mar 2020)

Hi Folks,

This is the research paper to which I referred above:

https://repository.usfca.edu/capsto...e/8&utm_medium=PDF&utm_campaign=PDFCoverPages

Head to Chapter 3, _Nutrient Influences_. And, home in on section 3.3.3. As I understand it, cyanobacteria are nitrogen-fixing bacteria so they can make use of atmospheric nitrogen. They appear not to be dependent on a source of nitrogen from nitrate, for example. But they need a source of phosphorus, which they can get from phosphate in the aquarium water. If I've got my facts wrong, then I'm leaning to @dw1305 to correct me. Therefore, reducing the phosphate concentration in the water seems to be key to preventing, and controlling, cyanobacteria outbreaks. The $64,000 question is - what is an acceptable phosphate concentration?

Obviously, lighting plays an essential part in the likelihood of cyanobacteria infestations. From what I've read, BGA (cyanobacteria) contains a pigment called phycocyanin, which has a peak response to light at a wavelength of 610 nanometres (nm). But, it has a wide bandwidth of responsivity to light from 560 nm through to around 630 nm. In colour terms, this is from green through yellow and orange to red. Many aquarium light fixtures emit light in this part of the spectrum. Just take a look at the spectra for aquarium lights - if your chosen product has a published spectrum, that is! In this respect, warm white LED lighting emits more of this part of the spectrum than cool white LED lighting. But, this is a tricky one. Some of this light is needed to make our plants look good. As always, it's getting the balance right - easier said than done!

JPC


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## jaypeecee (13 Mar 2020)

Andrew Reynolds said:


> My question is will the plants eventually out compete the cyanobacteria so that it disappears if I do nothing but normal weekly water changes, or should I do a 3 day black out or treat with something like Easy Life Blue Exit.



Hi @Andrew Reynolds 

As I understand it, there are several different types of freshwater cyanobacteria  - just to complicate things! I contacted Easy-Life, the manufacturers of _Blue Exit_. I asked them about this and here is what they had to say:

"Actually all cyano that can arise in freshwater tanks, can be removed with Blue Exit. Certainly this ‘most common’ cyano Microcystis aeruginosa".

There is a scientific paper that looked into the efficacy of _Blue Exit_ and also considered its toxicity to fish. Here it is:

https://mnet.mendelu.cz/mendelnet2013/articles/43_postulkova_817.pdf

I tried _Blue Exit_ and found that it did suppress the growth of BGA but did not completely eliminate it.

JPC


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## dw1305 (13 Mar 2020)

Hi all, 





jaypeecee said:


> As I understand it, cyanobacteria are nitrogen-fixing bacteria so they can make use of atmospheric nitrogen.


They can. 





jaypeecee said:


> But they need a source of phosphorus, which they can get from phosphate in the aquarium water.


They do, along with the other <"~ thirteen nutrients essential for plant growth">. Phosphorus is a very interesting one, because it is possible to have high PO4--- levels without <"developing phytoplankton blooms">.

The abstract from your link very much suggests that actually high ammonia levels are the factor that favour the growth of _Microcystis aeruginosa,_ but again it is back to high nitrogen and phosphate levels being the joint markers of eutrophication. 





jaypeecee said:


> As I understand it, there are several different types of freshwater cyanobacteria - just to complicate things!


There are, some that "like" low nutrient conditions and some that like eutrophic conditions. Have a look at the Lenntech web site <"General effects of eutrophication">. 





jaypeecee said:


> From what I've read, BGA (cyanobacteria) contains a pigment called phycocyanin, which has a peak response to light at a wavelength of 610 nanometres (nm).


They do along with chlorophyll "a" and various accessory pigments.

I have to admit I'm sceptical that manipulating the visible light spectrum can make much difference. This is the <"absorption spectra for six different  cyanobacteria species">.




cheers Darrel


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## Witcher (13 Mar 2020)

dw1305 said:


> I have to admit I'm sceptical that manipulating the visible light spectrum can make much difference.



I think the same can be said about most of the aquatic plants - no matter what kind of light I've used, it's intensity (plus nutrients of course) seemed to be far more important than its wavelength - never saw significant difference in growth by changing the colour etc.


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## jaypeecee (13 Mar 2020)

Hi Darrel,


dw1305 said:


> The abstract from your link very much suggests that actually high ammonia levels are the factor that favour the growth of _Microcystis aeruginosa,_ but again it is back to high nitrogen and phosphate levels being the joint markers of eutrophication.



Yes, on reading it again, the Abstract says that high ammonia levels do indeed favour the growth of _Microcystis aeruginosa_. But, in an established tank, is ammonia/ammonium likely to be the culprit? I wouldn't have thought so. Am I wrong? Is this a case of 'Old Tank Syndrome'?

Thanks for posting the absorption spectra for different species of cyanobacteria.

JPC


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## jaypeecee (13 Mar 2020)

Hi Darrel,


dw1305 said:


> I have to admit I'm sceptical that manipulating the visible light spectrum can make much difference.



I expressed my thoughts on this in https://www.ukaps.org/forum/threads/is-algae-worse-with-led-lighting.56212/.

JPC


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## dw1305 (13 Mar 2020)

Hi all, 





Witcher said:


> I think the same can be said about most of the aquatic plants - no matter what kind of light I've used, it's intensity (plus nutrients of course) seemed to be far more important than its wavelength


I always come back to the likelihood that photosynthesis probably only evolved once sometime before three billion years ago and that we only have one sun and it has a pretty steady spectral emission. That is a long time for natural selection to have polished the light interception properties of "plants". 





jaypeecee said:


> But, in an established tank, is ammonia/ammonium likely to be the culprit? I wouldn't have thought so


It is back to what that level is. If cyanobacteria "outbreaks" are associated with raised levels of organics then the trigger rise in ammonia level might be really small. Cyanobacteria  are like diatoms and pretty much universal on earth, I would guess all tanks will have some present at low levels. 





jaypeecee said:


> Is this a case of 'Old Tank Syndrome'?


I don't know, traditionally it was attributed to raised NO3 levels and loss of carbonate hardness. Microbial nitrification would be compromised by low carbonate levels, but we now know that a lot of nitrification in aquarium is by Archaea, which don't have the same requirements for high pH and carbonate hardness. Aged yellow water used to be looked on as a positive thing.

My guess would be that you would struggle to induce "old tank syndrome" in a planted tank if you had even a modicum of plant growth. 

cheers Darrel


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## jaypeecee (13 Mar 2020)

dw1305 said:


> I always come back to the likelihood that photosynthesis probably only evolved once sometime before three billion years ago and that we only have one sun and it has a pretty steady spectral emission.



Hi Darrel,

The daylight spectrum does change throughout the day for a given point on the earth's surface as the sun moves across the sky. Somewhere, I have some spectra showing the shift but I can't locate them on my PC. If I have a moment, I'll check again.

JPC


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## dw1305 (13 Mar 2020)

Hi all, 





jaypeecee said:


> The daylight spectrum does change throughout the day for a given point on the earth's surface as the sun moves across the sky.


It does, it is also different at different latitudes, due to the attenuation of the daylight as it passes through the atmosphere, but it is back to  "just one sun" since the inception of photosynthesis.

cheers Darrel


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## Franks (13 Mar 2020)

I got rid of mine while raising light levels and using H2o2.
Ironically, I did notice a spike in Cyano growth after "cleaning" the external filter. With brand new plants in and a month of daily doing H202 with filter running, the plants grew in and now I don't need to dose any H2o2. 80% of the bare sand substrate is now rooted plants. Dosing ferts daily with Co2 injection.

All clear.


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## jaypeecee (13 Mar 2020)

dw1305 said:


> If cyanobacteria "outbreaks" are associated with raised levels of organics then the trigger rise in ammonia level might be really small. Cyanobacteria are like diatoms and pretty much universal on earth, I would guess all tanks will have some present at low levels.



Hi Darrel,

I may have asked you this before but have you ever taken a sample of slimy BGA from an aquarium, taken it to your place of work and identified it? I ask specifically about the slimy stuff as this is obviously what @Andrew Reynolds has in his tank. But I've also seen a patchy type of BGA, which was more akin to BBA _in form_ but was blue-green in colour. According to Aquasabi, "Quite often, slime algae belong to the genus Oscillatoria (filamentous cyanobacteria)". This is supported by Paul Krombholz at The Krib (remember that?) who says:

"They used to be called bluegreen algae, but cyanobacteria is being pushed as the better name because it draws attention to the fact that they are not related to other algae, but are large, photosynthetic bacteria. Some of them have a bluish pigment in addition to chlorophyll. There are some species that can fix nitrogen, but the ones that take over aquaria are usually varieties of Oscillatoria, which does not have heterocysts, and I assume it does not fix nitrogen".

So, perhaps what we have/don't have in our tanks is not Microcystis aeruginosa after all. No less than 22 years ago, George Booth (also at The Krib) wrote:

"We had a mild problem with blue-green algae growing below the gravel line along the front of our acrylic tanks. I would suppose conditions there are good: light being channeled in via the plastic, no water movement, low oxygen, available nutrients (?)".

The plot thickens.

JPC


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## jaypeecee (13 Mar 2020)

Andrew Reynolds said:


> My question is will the plants eventually out compete the cyanobacteria so that it disappears if I do nothing but normal weekly water changes, or should I do a 3 day black out or treat with something like Easy Life Blue Exit. I have 3% Hydrogen Peroxide but am nervous of it killing my filter material?



Hi @Andrew Reynolds 

Cyanobacteria elimination, in my experience, is never easy. There are many factors at play. And we've talked about some of them here. I suggest that you read through the posts in this thread to see if anything resonates with you. Reduced intensity lighting in combination with _Blue Exit_ and good water flow/oxygenation may be worth a try.

Please keep us updated.

JPC


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## dw1305 (14 Mar 2020)

Hi all, 





jaypeecee said:


> Hi Darrel,
> 
> I may have asked you this before but have you ever taken a sample of slimy BGA from an aquarium, taken it to your place of work and identified it?


No I haven't. For whatever reason I've never had much in the way of obvious cyanobacteria, and if I need some I have a couple of <"_Cycas revoluta">_ and _Azolla_ from which the symbiotic cyanobacteria are very easy to extract.

I've seen scattered strings of cells (trichomes) in biofilm samples, but none of my tanks <"ever smell "earthy" or "pondy">, which is a pretty good indication that there aren't many Cyanobacteria present.

The only place where I'm likely to get a smear of BGA is very occasionally <"on the old leaves of _Pistia">._

I've had tanks with <"balls of _Nostoc_">, and I've just noticed some in the "moss" tank, where the moss forms a solid block at the water's surface.

cheers Darrel


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## jaypeecee (15 Mar 2020)

dw1305 said:


> For whatever reason I've never had much in the way of obvious cyanobacteria...



Hi Darrel,

My understanding is that you prefer the 'low tech' approach to planted tanks. If I'm correct in saying this, then, perhaps you don't have problems with cyanobacteria because you have 'low' lighting?

JPC


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## dw1305 (17 Mar 2020)

Hi all,





jaypeecee said:


> If I'm correct in saying this, then, perhaps you don't have problems with cyanobacteria because you have 'low' lighting?


@jaypeecee  yes I am strictly "low tech", and I tend to run the tanks fairly nutrient lean.

I have some tanks with <"higher intensity lighting">, but they tend to have a much heavier plant load. The bottoms of all my tanks are <"dark and gloomy places">, whatever light I have.

cheers Darrel


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## jaypeecee (17 Mar 2020)

Thanks, Darrel. As I said, the low(er) lighting may be one of the reasons why you don't have a problem with cyanobacteria.

JPC


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## dw1305 (17 Mar 2020)

Hi all, 





Franks said:


> I beat it by over-dosing H2O2 on a daily basis before lights on.


For those who maybe tempted to go down the H2O2 route I've just found an interesting aquaculture article on the use of H2O2  <"Removing cyanobacteria and associated toxins in aquaculture ponds">.

cheers Darrel


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## jaypeecee (17 Mar 2020)

Franks said:


> I've beat Cyano having been through it twice and nearly giving up. It wiped out all my plants it got that bad. It was growing off the plants and all over the substrate. it killed all the plants to the point there was no point trying to save them as they were too badly damaged.
> 
> I beat it by over-dosing H2O2 on a daily basis before lights on. Two capfuls of food grade 6% (approx 30ml directly into the water column with the filter running. Fish are unaffected, and while the cyano doesn't appear to die immediately, it started to reduce after a week. After a month, it was all gone.



Hi @Franks 

To what volume of tank water did you add the 30ml of H2O2? You say 'over-dosing'. I've never used H2O2 in an aquarium so I wouldn't know what would be considered a 'normal' dose.

JPC


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## jaypeecee (17 Mar 2020)

dw1305 said:


> For those who maybe tempted to go down the H2O2 route I've just found an interesting aquaculture article on the use of H2O2  <"Removing cyanobacteria and associated toxins in aquaculture ponds">.



Hi Darrel,

That's an interesting article. But I don't understand how the fish survived in water with an ammonia level starting at around 0.9 mg/l and then increasing to around 1.3 mg/l. And the pH was >8.8 throughout so we would be looking at NH3, not NH4+. Very odd. Am I missing something?

JPC


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## jaypeecee (17 Mar 2020)

... and I've just noticed the DO figures - typically 2.5 mg/l. 

JPC


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## jaypeecee (17 Mar 2020)

... I've come to the conclusion that there were almost certainly no fish in that aquaculture pond. It's just dawned on me! It was this statement that threw me:

"There was a spike in ammonia within 2.5 and 4.0 mg/L H2O2 ponds on days 7 and 8, respectively, but _these were within the tolerance of freshwater animals_ (my italics) and decreased after week 3 (Fig. 4c)".

But, then, it concludes:

"A limitation of this was study was not assessing the potential toxicity of H2O2 to fish. There are indications this would be safe, based on no apparent toxic effects to zooplankton at 2.5 mg/L and limited persistence in water; however, this will be tested in the future on juvenile channel catfish and largemouth bass".

JPC


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## Andrew Reynolds (22 Mar 2020)

Thanks for everyone's replies to my question. I hadn't realised there had been so many since I last looked.
I have gotten rid of the cyanobacteria now. I used UltraLife Blue-Green Slime Stain Remover which did the job. I have also planted quite heavily and renewed the sponges in my filter. I also upped the flow by adding another powerhead.

Here is my tank now (it needs the plants cutting back which is tomorrow's job).


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## jaypeecee (22 Mar 2020)

Andrew Reynolds said:


> I have gotten rid of the cyanobacteria now. I used UltraLife Blue-Green Slime Stain Remover which did the job.



Hi @Andrew Reynolds

Wow - what a transformation! Your tank looks great. I am envious. Whatever is in that UltraLife Blue-Green Slime Stain Remover seems to do a very effective job of eradicating Cyanobacteria. I can see that I will need to consider this treatment in future.

JPC


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