Will cyanobacteria go away when tank settles?

Andrew Reynolds

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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

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H all,
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
 

Witcher

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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).
 

Andrew Reynolds

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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?
 

Kezzab

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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
 

alto

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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
 

Franks

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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.
 

dw1305

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Hi all,
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
 

jaypeecee

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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
 

jaypeecee

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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
 

jaypeecee

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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
 

dw1305

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

s-of-six-cyanobacterial-species-in-the-growth_W640.jpg

cheers Darrel
 
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Witcher

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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.
 

jaypeecee

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Hi Darrel,
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
 

dw1305

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Hi all,
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".
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.
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
 

jaypeecee

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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
 

dw1305

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Hi all,
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
 

Franks

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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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