# Brown algae won't go away



## GillesF (29 Dec 2011)

Hi guys

I've had my nano tank (10l / 2.5 gallons) for several months now. It has had its share of algae due to bad CO2 management and filtring: brown algae, staghorn, BGA, thread algae, ...

By increasing the CO2 and nutritients and buying a better filter (200L/H) the thread algae and staghorn have gone away. The BGA needs one more black-out for the final kill. Only the brown algae persists. It only grows on the sand, not on the glass. 

Can anyone tell me how I get rid of it? I've already lowered the light somewhat by turning the lamp (cannot use another lamp) so it does not point directly towards the water. 

Best regards,
Gilles


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## ceg4048 (30 Dec 2011)

Hi Gilles,
              I reckon the same blackout that you'll use to kick the BGA will also kick the diatoms Try a 4 day blackout. How much light are you using over the tank? Persistent diatoms usually point to excessive light. If you must use the same light, you can always obscure the bulb with cheesecloth or similar until the tank stabilizes.

Cheers,


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## GillesF (30 Dec 2011)

Hi Ceg,

you are right. When I did my first black-out, the brown algae was gone too. Now it's slowly growing again (just like the BGA). I'm not 100% sure but the lighting is either 9w or 11w on 10 liter, so about 1w/liter.

Here's a picture of the tank. I tilted the lighting a bit backwards to create some shade.


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## ceg4048 (30 Dec 2011)

Hi mate,
            Yeah, that looks like a nice tank. The problem with the WPG rule, even though I refer to it frequently, is that it breaks down for really small tanks and for really big tanks. That's primarily because the PAR energy received by the plants is a function of their distance from the light source. In a small tank, the plants are very close to the bulb, so even though you calculate 4 WPG (which is very high for any tank) the PAR energy received might easily exceed the suggested 20-30 micromoles at the bottom of the tank because the light does not have a chance to dissipate over that very short distance.

 In large tanks the volume becomes important because it is a cubic function (L)*(W)*(H), so this number increases much more rapidly than does the single number that is the distance from the bulb (H), so if you do the calculation, the cubic volume value is so large that the wattage value required to reach the ratio of 2WPG or 3WPG becomes enormous, sending the resulting PAR value into orbit. Therefore the WPG value is really only useful at middling tank volumes like between 20USG-75USG. We know that most people have tanks within this range and that's why it easy, most times, to refer to WPG.

Hope this makes sense. 8) 

Cheers,


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## GillesF (30 Dec 2011)

Learned something new today, thanks.

So I can assume that 9w is quite a lot for 10-15cm height? Will reducing the lighting duration help?


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## spyder (30 Dec 2011)

Your tank dimensions as listed on the link are 31*18*24 cm I would of thought this is more than 10l unless you have a lot of hardscape in there.

9w sounds about reasonable for the tank, you can reduce the amount of time you are running the lights and/or add some floating plants to help reduce lighting levels.


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## GillesF (30 Dec 2011)

It's probably a different size then. 

Mine is more like 10x12x15cm


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## ceg4048 (31 Dec 2011)

GillesF said:
			
		

> So I can assume that 9w is quite a lot for 10-15cm height? Will reducing the lighting duration help?


 Well, especially if the bulb is a T5 as opposed to a T8, being only 4-6 inches away means that the plant is almost on the surface of the bulb, so yes that's quite a lot of PAR. We don't really know what the energy levels are without measuring it directly with a PAR meter. As always though, high energy levels such as this may not be a problem if the flow rates are high, if the CO2 injection rates are high and if the nutrient loading is also high. It's a lot easier though to just shade the lamp directly or to use floating plants to block some of the light entering the tank.

Persistent diatoms are a sure sign that the tank is suffering from too much PAR. This does not mean that you will never be able to use that much light later on when the tank system has gotten stronger, only that right now, the plants are having difficulty handling that amount of energy.

Cheers,


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## GillesF (31 Dec 2011)

Hi Ceg,

It's a 9w fluocompact lamp. I do not have a PAR meter so I won't be able to determine the energy levels. I guess shading is indeed the best option for now.

I'm injecting CO2 at 1bps but still adjusting. Almost there though. The flow is pretty good, although I expected more from my 200l/H filter. I can see bubbles throughout the entire tank though, even at the opposite side of the atomizer, so I guess that's a very good sign.

Thanks for the info.

Gilles


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## GillesF (2 Jan 2012)

Ceg

any idea if I can use a bandage instead of cheese cloth?

*edit* or maybe use this?


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## GHNelson (2 Jan 2012)

GillesF said:
			
		

> Learned something new today, thanks.
> 
> So I can assume that 9w is quite a lot for 10-15cm height? Will reducing the lighting duration help?


Hi Gilles
How long do you have your light on :?: 
hoggie


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## GillesF (2 Jan 2012)

It's @ 7 hours.

That IKEA lamp is 4,5w by the way, half of what I have now.


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## GHNelson (2 Jan 2012)

Hi Gilles
Nice little aquarium :arrow:http://nascapers.es/tienda/product.php?id_product=579
Your aquarium holds 13 litres....I would reduce your lighting to 5 hours and do small water changes about 2 litres every 2 days...and lightly gravel clean do this for a couple of weeks.
hoggie


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## GHNelson (2 Jan 2012)

Mine is more like 10x12x15cm

I wouldn't have thought so this would be 2 litres...unless its a micro size 
hoggie


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## GillesF (2 Jan 2012)

You are absolutely right, I was wrong with the dimensions.
So I guess it's about 10 liters of water (13 liter - plants, sand, ...)?

The tank is undergoing it's second black-out, no lighting for 5 days. Hope this will kill the BGA for good.


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## GHNelson (2 Jan 2012)

Hi Gilles
You could try a black-out....I just think your aquarium is going through the immature stage and using that length of lighting is causing your problems.
Keep us posted on how you progress after the black-out.
hoggie


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## GillesF (2 Jan 2012)

I will.

During the last black-out the BGA took quite a beating but was able to recover. Let's see if it survives this one   

I've also bought some new glass diffusers and bubble counters. Looking forward to installing it.


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## ceg4048 (3 Jan 2012)

GillesF said:
			
		

> Ceg
> 
> any idea if I can use a bandage instead of cheese cloth?
> 
> *edit* or maybe use this?


Yeah mate you can use any material you want; lace, pantyhose, bandage, business cards, printer paper, post-it notes, whatever....

That's a nice looking lamp. I couldn't read the Flemish (or is that Dutch?). I guess it's an LED? Yeah, doesn't matter, any light works. 

Someday, PAR meters will be available at the local pharmacy....

Cheers,


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## GillesF (4 Jan 2012)

It's Dutch (Flemish is a more like a dialect). I'll probably buy the lamp and test it out, seems safer and easier than a bandage. Thanks again for the help all of you.


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## GillesF (7 Jan 2012)

The aquarium just came out of its 4-day black-out. So far so good, no brown algae or BGA to be seen.

I've also replaced the ligthing by the IKEA LED lamp and I simply LOVE the shadows it makes. If I ever get a bigger tank I'll definitely go for LED again.

I do think that one  corner is a bit too dark because it falls under the shadow of the filter outlet but we'll see how the Eleocharis Acicularis react to that. It's an easy plant and with good CO2 it should work.

NO3, PO4, trace elements etc have been added too. Looking forward to seeing the result in a few months!


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## GillesF (11 Jan 2012)

Looks like I completely killed the BGA. The brown algae is still there though ...
Moved from 9w to 4,5w, full EI dosing and better CO2. It only grows on the substrate (sand). Maybe it just likes the sand?


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## ceg4048 (11 Jan 2012)

Yeah it should go away in a couple weeks now that you lowered the energy levels. Lots of water changes will help.

Cheers,


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## GillesF (11 Jan 2012)

ceg4048 said:
			
		

> Yeah it should go away in a couple weeks now that you lowered the energy levels. Lots of water changes will help.
> 
> Cheers,



Allright, will do that, that's easy anyway with a nano


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