Blue green algae/cyanobacteria

[wisecrackerz]

I'm relatively sure this thick, dark, blue green slime growing in a flat even coat all over everything in my tank (especially leaves of plants) is cyanobacteria, also known as blue green algae.

I don't have a phosphate test, but I'm relatively sure this much of this gunk means I have a fairly serious phosphate problem (as in too much). How do I get rid of this?!

I can't add any more plants; my nitrates are next to nil as it is (dirted plant only). Whyyyyyyyyy phosphates, whyyyyyyyyy?!

 

[Dom90]

Maybe it's a result of over feeding or too much uneaten food?

 

[LiterallyHydro]

Are you able to get a phosphate test kit? They aren't very expensive and could tell you if the phosphates really are the problem here.

 

[Dom90]

You can get a box of Fluval Clearmax to trap phosphates if you want.
Haven't had personal experience with it yet though.

 

[Aquarist]

https://www.fishlore.com/aquariummagazine/apr08/cyanobacteria.htm





For future reference and for those that may not know about cynobacteria, check out the links above.

Ken

 

[wisecrackerz]

Solution implemented. Further ideas?

Thank you for all the great suggestions!

In this particular case, I can be 100% sure that the issue is not uneaten food. It is a plant only tank, which means there are no animals (except a few microorganisms, I'm sure), and thus, no food. But, if I ever do get cyanobacteria in a fish tank, I'll keep over feeding in mind as a possible source of extra PO4-.

Unfortunately, none of the LFSs in my area carry a PO4- test kit, but I do plan to order one, now that I know they are commercially available. To me, in a tank containing only plants, which were all hydrogel-grown, a blue green algae problem of this severity is a pretty solid indicator of a high [PO4-], but if it's coming from my tap water, I need to know!

The links were especially helpful, thank you, Ken. So far, I have done the following; let me know if you think of anything else I should do.

• Thoroughly cleaned slime off plants, drift wood, rocks, and glass. Removed as much as possible from dirt substrate, but still more left than I'd like, tbh.
• Found and removed all parts (roots included) of some rotting plants (semi-aquatics)
• Did 75% water change.
• Removed extremely old activated carbon from filter (d'oh! SOOOO embarrassed that I didn't do thorough filter maintenance when I started this tank up again a couple months ago.)
• Saved out my BB medium in a plastic baggy with some aquarium water in the fridge.
• Added a fake moss ball (temporary) which supposedly has some kind of resin in it which absorbs PO4-, NO2, and NO3, for while my plants are less active during black out.
• Dosed with tetracycline (a challenge for a 5G tank with the locally available powder packets).
• Turned off tank lights, and draped with a towel for complete blackout.
• I plan to complete the course of tetracycline (includes another large water change 2 days in), maintain blackout for 3 days, and remove any more algae and plant bits I can get out of the tank.

Am I missing anything?

 

[LiterallyHydro]

Looks good to me. Have you looked into a product such as I've used it in the past in a reef tank to good success. I imagine it would work for you as well unless it's the tap water that's raising your phosphates.

 

[lookimawave]

Has anyone tried Easy Life Excital?
Or Ultralife Slime Remover?

 

[AlyeskaGirl]

The cause of Cyano is most often very low nitrates. Dirty substrate or filter can also bring it on.

I had it growing down in the substrate against the glass. I suspected due to a dirty substrate but I also had low nitrates. Phosphates in my high tech tank is around 2-3ppm as I dose KH2PO4.