# GDA & hair algae - CO2 not an option.



## idris (May 18, 2011)

My 250L low tech tank has been set up for about 6 months. 
I've had GDA for about 3 months and have started getting some green hair algae, most notably on Wisteria leaves near the surface. 

From what I've read, low CO2 is a likely cause, but gaseous CO2 isn't an option for me and as I have Vallis, liquid CO2 substitutes are not ideal. (My limited experience of liquid CO2 supports the advice I've seen that it's not good with Vallis.)

Light levels are low (80W for 250L) and the photoperiod is about 6hrs.
I don't dose with ferts and do 10-20% water changes each week.
The filter flow rate is probably a bit lower than the hi-tech guys would want. 

As the GDA doesn't seem to be diminishing, and the hair algae has started appearing, any suggestions, without going more hi tech?


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## oldpunk78 (Nov 1, 2008)

What type of lamp is in your light fixture? How high above the water's surface is it? Reflector quality? How's you plant growth? Plant load? Substrate? Fertilizers? Fish load? Water quality?

These are all things are relevant to your problem. knowing these details could help. Without knowing more, I would just suggest raising your fixture a little higher and seeing what happens. Light level is highly import for keeping algae at bay in non-co2 tank.


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## VeeSe (Apr 16, 2011)

The first thing that I also thought of, like oldpunk78, would be to lower your lighting level, either by raising the light higher away from the tank or by some other means.


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## idris (May 18, 2011)

Sorry for the lack of necessary info - my first real algae question. So...

What type of lamp is in your light fixture?
2x 30W T8, 36" tubes (just checked - slightly less than I thought). One is a "moonlight" blue, the other is one marketed for plants. (I have since learned these aren't necessarily the best but I'm stuck with them till they fail.)

How high above the water's surface is it?
Probably only about 1.5". They can't be moved due to the design of the tank and hood.

Reflector quality?
They're nearly a good as mirrors.

How's you plant growth?
Vallis has grown about 1ft in the last month and putting out runners in all directions.
Amazon Swords are about 1ft high and continue to produce new leaves. Very few leaves have died.
Crypt Wenditti doesn't seem to be growing obviously any more, but looks healthy. I think it's the brown variety, but it's more green than brown these days.
Wisteria ranges from 6" high to 2'6". On most of the stems the leaf growth is in the top 6" with lots of runners below. I've cut back a couple of the taller stems recently and they are starting to show some leaf growth lower down, though their growth seems slower than when they were first planted.
Dwarf hair grass is up to about 4". It hasn't spread much in the last couple of months and some has floated free. Not sure if this is because it's been uprooted by fish or pushed out by the Wisteria.
Round Pleia has spread well over the wood it's attached to and some is spreading across the substrate.
Taiwan moss continues to grow well, both in terms of thickness and area covered.

Plant load?









Substrate?
Akdama, ranging from 1" to 4" deep.

Fertilizers?
None.

Fish load?
6 Otos. 12 Neons. 6 Dwarf Rainbows. 3 Dwarf Gouramis. 4 Kilifish. 6 Amano shrimp. 3 Assassin snails.

Water quality?
Gh = 10deg (German)
pH = 7.5
NH4 < 0.25ppm (indicator fluid is slightly darker than 0ppm but not as dark as for 0.25)
NO2 = 0ppm
NO3 = 10ppm


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## Hilde (May 19, 2008)

idris said:


> 1 Light fixture 2x 30W T8, 36" tubes
> One is a "moonlight" blue, the other is one marketed for plants.
> 
> 2 Plants:Vallis, Amazon Swords, Crypt Wenditti, Wisteria, Dwarf hair grass, Round Pleia, Taiwan moss
> ...


1 Blue light promotes algae. Take out the blue light.

2. Fish load not balanced with plants for absorbing waste. Add hornwort or some floaters

3. Co2 additive that doesn't affect Vals is Brightwell aquatics FlorinAxis. Check Ebay for it.


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## zergling (May 16, 2007)

Hilde said:


> 1 Blue light promotes algae. Take out the blue light.


Have you used "blue" lights before? I've experimented with ATI Aqua Blue Special, ATI Blue Plus, ATI Purple Plus, and one or two actinic bulbs -- they don't promote algae. It's all about your CO2 and dosing matching up with your lighting levels.

idris -- are you sure it's Green Dust Algae, or Green Spot Algae? 

GDA looks like dusting on your glass, and can be removed by wiping off. If this is what you have, you don't have much of a choice but to leave it undisturbed and let it go through its life cycle. It will go away after 3-4 weeks, then you can do a large water change.
Green Spot Algae look like round dots of green and can't be scraped off easily (takes some elbow grease). This is usually brought by low CO2 and/or low phosphates. 

There's also lots of types of hair algae, but ammonia is probably the cause of what you have. Just do frequent water changes and remove as much of the hair algae as you can. When your ammonia is constantly zero, you can consider adding a few more amano shrimps to eat up what's already there.

There's quite a few algae guides there, this one is what I like to refer to:
http://www.theplantedtank.co.uk/algae.htm


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## idris (May 18, 2011)

I'm pretty sure there's GDA and it looks as you describe.
That said I think there is a little GSA as well. 

I've looked at Jame's Planted Tank before and most of the contenders for the hair algae seem to be connected to CO2. But adding CO2 is a difficult option for various reasons.

I don't really know how to remove the hair algae as most of it is on plants like Vallis and Wisteria, and the dimnensions of the tank make it difficut to work inside without risking uprooting a lot of plants.

I'll try more water changes in the short term, and leave the GDA to sort itself out.


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