# BGA (Cyanobacteria) UNDER the substrate



## Big_Fish (Mar 10, 2010)

My 'test tank' is experiencing an issue with Cyanobacteria, which at the moment is more a nuisance than anything else... but I thought I should ask  

Cyanobacteria has appeared on the glass at the front of the tank, roughly 1/2 inch BELOW the surface of the substrate. As far as I can tell, it's not causing any immediate problems but I'd like to get rid of it nonetheless. it does NOT seem to be getting any worse, and I know what caused it in the first place... the initial cause HAS been resolved.

I'm thinking about simply blocking off the front of the tank, from the top of the substrate down.
(leaving the lights and everything else ON as normal...) the Cyanobacteria is not 'new' ... it formed about two months ago, but I only recently discovered it is Cyanobacteria, and not simply GSA.

whaddya think? should I just give the entire tank a 3 day blackout or go directly to direct application of peroxide? (direct application will mean digging a trench in the substrate to gain access.... something I'd prefer to avoid)

questions, comments, criticism always welcome.
Thanks in advance. :yield:


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## JeffyFunk (Apr 6, 2006)

What's your substrate? I know that in my soil-based tanks, if I let the sun directly hit the substrate, often times I get a layer of algae under the substrate. It's not harmful to the tank, but it is unsightly. The algae is probably growing from the photo-oxidation of Fe(III) to Fe(II). I usually just cover up the substrate layer in my tanks w/ black tape (cause it matches my trim). 

If you want to get rid of it, the easiest thing to do is also to cover the substrate layer. If you don't want to go that route, you can usually "scrape" the algae layer away using a credit card or a spatula by pushing the algae to the bottom of the tank where you can't see it. This is only a temporary fix obviously, but it's simple enough that out of sight, out of mind.


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## Big_Fish (Mar 10, 2010)

sorry should have mentioned.  

substrate = flourite. (regular redish stuff)
... electrical tape was EXACTLY what I'd planned on using.
I'll give it a whirl tonight (with some before/after pics)


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## Big_Fish (Mar 10, 2010)

blackout WORKED. 
at 7 PM the 19th I blacked out HALF the front of the substrate.
I pulled it off to have a look at 7PM last night (the 21st, 48 hours later.)
pics tell the story better than I.


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## londonloco (Sep 25, 2005)

First off, nice tank. I have same problem in my 120g. I'm going to try the black tape also. It will be interesting to see how long until the algae reappears. Thanks....


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## Big_Fish (Mar 10, 2010)

Thanks, Londonloco ... 
this one started out as my main tank... and ended up being the 'test dummy' for anything I could throw at it...
(it's become a real jungle... plants tossed in akimbo without regard to design or effect.) a very simple 'will THIS grow well for me?' tank.
it has served it's purpose well, and now it's begging for a re-scape. 
THAT process starts this weekend.


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## xavierj123 (Aug 24, 2008)

Hey Big Fish ! I like your "will it grow" tank. Great idea!


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## flashbang009 (Aug 6, 2009)

you could also take a pipette and squirt hydrogen peroxide down into the substrate where you have the problem. I guarantee it will kill the algae within 3 days, and you won't "hurt" your plants like a blackout will.


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