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Cyanobacteria on filter?

Anomander

Member
Joined
24 Apr 2024
Messages
67
Location
London
1. 60ish litres
2. Setup is nearly 3 months old
3. Two sponges (30 ppi & 20ppi) attached to powerheads at opposite corners of tank, one with venturi and duckbill pointed towards surface.
4. 8hrs light via Ciano LEzdCLA60 (8W – 18VDC);
5. Fine Unipac silver sand substrate
6. Low tech
7. Per week: 6ml TNC Complete, 0.8ml TNC iron, 1.6g Epsom Salts
8. 50% WC per week (but switching to 20% due to new inhabitants)
9. Anubias, Java Fern, Java Moss, and Salvinia planted at initial setup
10. 8 neocaridina shrimp

Hello all,

I was wondering if anyone could identify this growth on my sponge filter (please see image)? It's a 30ppi poret sponge attached to an Aquael Pat Mini. My fear is that it's Cyanobacteria (even though there is no discernible smell, the colour seems to match). It started as a small patch but then spread over the course of a week or so.

There is also another smaller sponge with a powerhead showing similar growth but to a lesser extent (2nd image). This second sponge is not exposed to as much light as the larger sponge due to floating plants above it. Finally, a similar growth appears in patches on the glass (3rd picture), as well as some below the sand substrate at the front of the glass. However these last growths have been stable for several weeks and have not grown. There is no growth on the sand substrate itself. The large sponge has the most significant amount of this growth overall, both in size and speed.

If it is Cyanobacteria, what would be the best way to clean it off the sponges? I tried swishing it in a bucket of aquarium water but it didn't remove much of it. Would siphoning it directly off the sponge be detrimental to the beneficial bacteria being housed there (the sponge has been running for nearly 3 months, same age as the tank)? It's a low tech tank, 8 hours of light per day.

Thank you for any help, and happy to provide any further info.
 

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For algae help, please read the guidelines:

 
Yeah that's cyano alright. I've had the exact same thing happen on sponge mattenfilters in newly set up tanks. In my experience it didn't really penetrate the sponge at all and was fairly easy to peel off in big sheets using a pipe cleaner brush.
I've only ever managed to totally get rid of cyano with blackouts though, sometimes more than one, and then returning to a lower light level than during the cyano outbreak. I think it's hard to predict the results of a cyano outbreak though and sometimes it may be best left to just run its course. Sometimes it never gets that bad and eventually recedes and then completely disappears on its own but it can obviously also completely blanket an entire tank in a worst case scenario.
I've also seen cyano recede below the surface of the substrate and stay there for years only visible against the glass without ever appearing above. It's a weird one.
 
Yeah that's cyano alright. I've had the exact same thing happen on sponge mattenfilters in newly set up tanks. In my experience it didn't really penetrate the sponge at all and was fairly easy to peel off in big sheets using a pipe cleaner brush.
I've only ever managed to totally get rid of cyano with blackouts though, sometimes more than one, and then returning to a lower light level than during the cyano outbreak. I think it's hard to predict the results of a cyano outbreak though and sometimes it may be best left to just run its course. Sometimes it never gets that bad and eventually recedes and then completely disappears on its own but it can obviously also completely blanket an entire tank in a worst case scenario.
I've also seen cyano recede below the surface of the substrate and stay there for years only visible against the glass without ever appearing above. It's a weird one.
Thanks very much for the info, I've always assumed the worse when it comes to Cyano but I will pounce on it when it appears and hope for the best!
 
Yes I believe that is cyano as well. I have had big problems with it in the past due to low nitrates so maybe check you have high enough levels and your plants aren't eating them all up. Extra dosing and water changes cleared mine up but can be multiple reasons for it not just low nitrates. Hope this helps.
 
Yes I believe that is cyano as well. I have had big problems with it in the past due to low nitrates so maybe check you have high enough levels and your plants aren't eating them all up. Extra dosing and water changes cleared mine up but can be multiple reasons for it not just low nitrates. Hope this helps.
Good point about the nitrates, I have a lot of floating Salvinia which could be hoovering up the nitrates as it grows pretty rapidly. Would increasing my TNC Complete dose help with that?
 
How are you cleaning your sponges? It's just your description of swishing sounds like maybe you are a bit nervous of over cleaning? When I clean my sponges I'm giving them a good squeeze/shake/crumple in tank water until the water is coming out pretty clean. With two sponges you can do them alternate water changes. If your sponges are very clogged that could be reducing your flow and making a nice growing medium for the cyano.

I had bits of it for ages, never seemed to really get worse, but not better either. Increase the ferts made difference though, so that could be something to try too. If your tanks only three months old, it may also just be going through a teething stage.
 
How are you cleaning your sponges? It's just your description of swishing sounds like maybe you are a bit nervous of over cleaning?
Yes, exactly this. I was going off advice from Aquarium Science that I should hardly clean my sponge filters for the first few months until the bacterial colony is fully established. As such I've been very hands-off with the cleaning.

Increase the ferts made difference though, so that could be something to try too
Could you recommend a good initial increase from 6ml TNC Complete a week?

Thank you for your helpful advice.
 
Can you post a full tank photo and one of your floating plants? Have you seen the duckweed index? That will help you gauge fertiliser need.
 
Hi all,
I was going off advice from Aquarium Science that I should hardly clean my sponge filters for the first few months until the bacterial colony is fully established
You don't need to worry too much, <"Aquarium Science"> keeps fish at <"insane stocking rates"> in <"tanks without plants">. It is different for planted tank keepers, we have plant / microbe biofiltration and are never entirely reliant on the microbes in the filter.

cheers Darrel
 
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Can you post a full tank photo and one of your floating plants? Have you seen the duckweed index? That will help you gauge fertiliser need.
Yes I will do so but am currently at work and going out after, so it may be this weekend
 
Hi all,

You don't need to worry too much, "Aquarium Science" keeps fish at <"insane stocking rates"> in <"tanks without plants">. It is different for planted tank keepers, we have plant / microbe biofiltration and are never entirely reliant on the microbes in the filter.

cheers Darrel
Good to know, thank you. As a historian I should know that context is everything!
 
Hi all,
As a historian I should know that context is everything!
That is it, <"microbe only"> biofiltration is all your eggs in one basket (or the <"Maginot Line">), and a <"pretty unstable basket"> at that.

<"Plant / microbe"> biofiltration just gives you "belt and braces" and means that there isn't a single point of failure. You also have the net oxygen production of the submerged plants (both in the water column and <"in the substrate">), this extra oxygen is a massive advantage for microbial nitrification, because nitrification is an <"oxygen intensive process">.

The substrate is actually going to provide some of the <"same ecosystem services"> that the Matten Filter (HMF) would, and my personal preference would be to give the sponge an occasional clean.

You can possibly use the water level difference between the tank and behind the sponge to indicate when to clean. I'd go on "difference noticeable by eye" = "give it a rinse".

cheers Darrel
 
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You also have the net oxygen production of the submerged plants (both in the water column and <"in the substrate">), this extra oxygen is a massive advantage for microbial nitrification, because nitrification is an <"oxygen intensive process">.
A question just occurred to me: do slow-growing submerged plants produce less oxygen than fast-growing ones? I'm just conscious of the fact that my fast-growing plant (Salvinia) won't be contributing any dissolved oxygen into the water, and my submerged plants are all slow-growers. I have about 30% of the water surface uncovered and agitated by a powerhead with duckbill pointed up and Venturi attached.
 
Hi all,
A question just occurred to me: do slow-growing submerged plants produce less oxygen than fast-growing ones?
They do. The growth rate of a plant is dependent upon the CO2 incorporated and for every molecule of CO2 a molecule of oxygen is evolved. If nutrients aren't limiting and you have sufficient PAR? A <"fast growing plant"> will incorporate a lot more CO2 (and nutrients) and evolve a lot more oxygen.
I'm just conscious of the fact that my fast-growing plant (Salvinia) won't be contributing any dissolved oxygen into the water,
No, it won't, I'm going to say that all the stomata are on the <"upper (adaxial) leaf surface">. I've had a thought about Salvinia spp. specifically, and that is that the "root" is actually a "leaf", so it may contribute to submerged gas exchange? I'll see if I can find out.
I have about 30% of the water surface uncovered and agitated by a powerhead with duckbill pointed up and Venturi attached.
That should allay any worries.

cheers Darrel
 
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