Black Brush Algae

[scouse_andy]

I've been suffering from an algae problem in my low-tech planted tank, the tank is fairly recently cycled, I've gone through the brown diatom phase and, by looking at Jamesc's website, I think I'm suffering from an outbreak of black brush algae. The algae has coated the rock background but mainly at the height of the filter outlet (fast flow area). It is also all over the leaves of my slow growing plants, the glass at the front of the tank, the sand substrate and caught in the Cabomba leaves as it has been blown around the tank.

I bought a fine mesh net to catch as much as possible, scrubbed the rock background and syphoned the substrate a bit too, I've caught most of it but I guess it will be back with a vengeance soon.

Does anybody have any advice on the algae, do you think it sounds like BBA? It looks black in the tank but then slimey green, slight blue tinge out of the tank (doesn't smell though so I don't think it is BGA) it is slimey but does wipe off pretty easily from leaves with fingertips or tapping the net on the stem. If so, what is the best way to eliminate it? I’m kind of fire fighting at the moment, and expect it back soon! My light levels are low (1.25WPG) 12 hours photoperiod with a 2 hour siesta. Loads of algae busting plants plus hornwort floating around.

I could wait it out and manually remove what I can if things are likely to improve of their own accord as the tank matures and the plants grow. Otherwise what about dosing Flourish Excel (double doses?) If I did this, perhaps 2 sevenths of the recommended weekly dose per day (if you follow!) would I need to do big water changes or not and would my fish be alright? This does not appeal to me if I am havig to change 120 litres per week. If it is down to uneven CO2 levels then it must be due to water changes as that is how my tank acquires its CO2. As my nitrates are being consumed by my plants, I plan no water changes over the next month or so, so maybe it will clear up by itself.

Any advice here would be most welcome. I suppose the last resort would be a 3-4 day black out with no light at all. Would this do the job for sure?

Thanks in advance.

 

[Liam]

From your description it sounds like bga as bba wont come off easily, you have to scrub to get bba off wood. Bba doesn’t feel any more slimy than a plant. If its bga its good news in a way as its easier to get rid of with the three/four day blackout. Bga does normally smell, though it varies in how strong the smell is. A pic would be useful if you are not sure.

 

[scouse_andy]

Here is a photo I took before it got too bad. It is slimey and does come off easily and seems to start on the substrate at the front by the glass.

If it is BGA is it as simple as completely covering the tank for 4 days with no peeking at all or do I need to get rid of any visible trace of algae before I start?

 

[Liam]

Yeah BGA it is, am 99% certain. Its recommended to remove as much as you can with a fifty percent water change, then do the blackout and do a 50% wc after the blackout to clean up the dead algae. The fish will be fine with this. Some choose to run an air stone in the tank as its so covered that there may not be enough oxygen, that depends on fish load, I have done it without an airstone and all fish seemed happy after their big sleep. It is said to be triggered by low nitrates. I have used a small tube to suck up the bga during the water change it takes it off easily and removes it. Its ages ago since I read the Diana Walstead book, she writes about it I think so you could have a look at what she says about it.
good luck on getting rid of it.