[niclas90]

I've got these three 20 litre nano tanks, all suffering from unstoppable GDA (atleast that's what i think it is). They've been running for three months, and i dont know what to do.

CO2-supply is around 30 mg/l.
The light is a Daytime Cluster 70.3, with one 11W cluster over each tank (6500K).
I dose Tropica Premium twice and week, and change water once a week.
NO3 and NO2 are at 0 mg/l in all three tanks.

High-res pictures of the issue: Algae - Album on Imgur

Any suggestions? I really dont know what to do.

 

[Hoppy]

It looks like you have several algae problems in those tanks. One thing that can lead to algae of all kinds is excessive light. With more and more light you have to have more and more CO2 dissolved in the water, better and better cleanliness of the tank, water, filter, etc., and more certainty that you are not stunting the plants growth by having any nutrient shortage. If you use a layer of gray fiberglass window screen as a light filter on the light fixtures you will drop the brightness (PAR) by about 40%, and it is very easy to try this.

 

[dzega]

not only GDA you have there.
definetly too much light with respect to plant photosynthesis. hair algae tells you that.
either lower the light output or boost co2 and nutrients. no3 to start with if thats 0.

edit: and drop some amano shrimps inthere to assist you. 3 per tank or something like that

 

[discuspaul]

For the GDA, try this - it works:

http://www.plantedtank.net/forums/2...-algae-everywhere-after-coming-back-vaca.html