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Brown algae won't go away

GillesF

GillesF

Member
Joined
21 Jun 2011
Messages
279
Location
Belgium
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
 
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,
 
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.
 
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,
 
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?
 
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.
 
GillesF said:
So I can assume that 9w is quite a lot for 10-15cm height? Will reducing the lighting duration help?
Click to expand...
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,
 
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
 
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?
Click to expand...
Hi Gilles
How long do you have your light on :?:
hoggie
 
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
 
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.
 
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
 
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 :D

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

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

*edit* or maybe use this? :D
Click to expand...
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,
 
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.
 
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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