tiny bit of Brush Algae, should I worry?

[alinwrkshp]

I just recovered from a nasty case of BGA and have been dosing with KNO3 based on some advice seen here. So far pretty good. I have been getting a little hair/thread algae on the drift wood, but that doesn't really concern me. As long as it doesn't grow on the plants (it doesn't), I think it adds character to the tank.

What does concern me though is the little spots of Black Brush Algae growing in one spot in my tank. I know through reading this forum that this means my DIY CO2 injector isn't cutting it right now. What makes me curious about this though is that, it's only growing on the bottom of one of my pieces of driftwood that is running horizontally across my tank. This driftwood is sitting right in the path of one of my Oxygen bars. So it's litterally being bombarded with Oxygen Bubbles.

The BBA isn't growing on the top of the wood, and is nowhere else in the tank. So does this mean that the Oxygen Bar is overpowering the CO2 in that one spot and thus allowing room for the BBA to flourish.

Next question is what should I do about it? Should I be worried, it is only growing in one small spot in the tank that can easily be taken out/Cleaned and moved to a new spot (away from the Oxygen Bar). Or is this a sign of things to come and that just happened to be the "canary in the mine"?

Thx in advice for the help guys!

 

[Blinky]

Are you injecting CO2 and using an airstone/bubble wall at the same time? (I'm assuming you're referring to a bubble wall when you say oxygen bar). If this is the case, any CO2 you inject is probably being flushed back out of the tank again as a result of the surface agitation created by the bubbles.
Generally speaking, an overgrowth of algae is a sign that something's not quite balanced in a tank. Once you correct the imbalance, the problem should resolve itself.
Can you provide more details about the tank? Any test results, along with tank size, lighting, how long it's been up and running, inhabitants (including plants), lighting, ferts, and any other significant information will help people come up with answers.

 

[alinwrkshp]

The tanks a 55 gallon, and it has been up and established for over a year. Your right about the bubble wall, but the CO2 hose is actually running up over to the intake of my AquaClear. I read that one of the easiest ways to get the CO2 dispersed is to let it run into the intake of your filter. It has been working great for a long time, over 4 months.

I just got over some BGA, brought on by a nasty filter issue. Used antibiotics to kill it, then found this site and the advice given about KNO3, so I started dosing about 1/2 tsp of that every other day. This was about a month ago that I did that. I also use the leaf zone plant food about once a week. I have two large(5"-7") cichlids in there producing a ton of waste and 4 smaller(under 3") fish in there as well.

I have a grip of water sprite and hornwort, some moneywort and a pretty badly beaten sword. The cichlids apparently don't like the sword. The water sprite flourished when I added the CO2, it now takes up 1/3 of the length of my tank, from just a few bunches over 4 months ago. I have been having really great growth from all of my plants. Just under 3/watts per gallon of full spectrum bulbs. I have roughly about a 10hr photo period and I was cleaning the tank twice a week before I read the post about the KNO3. I was afraid I had too many nitrates in the water, but I figure the dirty filter media was the cause of the BGA, since there's no sign of it now. Since reading that post, I have dropped the cleanings down to once a week, or about every 4-5 days, whatever my clean freak nature will allow me to get away with.

Is black brush algae or is it bacteria like BGA? I am going to just take the driftwood out, since it's the only spot in the tank that it's growing at. I have other driftwood in the tank, but the only spot it's growing is right where the wood is exposed to the bubble wall. I thought that was a bit odd, and figured that the CO2 is being overpowered in that spot by the oxygen and thats why it is allowed ther an not anywhere else. I have other driftwood and plenty of rock work, but the BBA is only on that one piece and only right where the bubble wall intersects.

 

[Blinky]

A bubble wall adds air to an aquarium, not oxygen. Here's how I understand things, I hope I'm explaining this correctly - CO2 and O2 are contained in the water column at a molecular level, and they're exchanged at the water surface. When there's surface agitation (as with a HOB filter or air bubbles breaking the surface), this exchange rate increases, and the injected CO2 will be flushed out, and exchanged for atmospheric O2. Running the CO2 into your filter is a good way to get it into your tank, but having a bubble wall that causes surface agitation will flush most/all of the CO2 that ends up in the water right back out.
CO2 and O2 aren't dependent on one another in the water - you can have a tank with high CO2 levels that is supersaturated with O2 (this is when you see 'pearling').
The fact that the algae is near the bubble wall is possibly due to the fact that it likes faster-moving water. Algae doesn't grow well in high oxygen levels, so I doubt it's anything to do with that.
There's an easy way to check your CO2 levels. You can measure the tank's pH and KH, go to Chuck's Planted Aquaria pages and use the chart. You can also download a nutrient & CO2 calculator for your computer, it's very handy

 

[alinwrkshp]

thanks for the explanation! Based on your explanation, I am chasing my own tail here! The bubble walls are left over from a high temp ich treatment. I'll have to take a look at the recommended sites, your explanation of the fast moving water makes a lot of sense. thx for the info!

 

[Blinky]

No problem
If you take a look at the sticky on algae and read some of the old posts in the planted forum related to algae you should be able to find loads of info that will help you conquer it.

 

[alinwrkshp]

well, i took out the driftwood and cleaned it all up. Then removed one of the two bubble bars. I also changed out my CO2, found a recipie that used Jello and is supposed to be more stable.

So far so good, but think it's to early to tell. Like I said that was the only spot it was growing so, here's me crossing my fingers!

Thanks again.