# Green film on the surface



## Midnight (12 Mar 2009)

Help
I came home after a  few days away to find a green film on the surface of the tank. What kind of algae is it?
I did a 50% water change but it's still there. 
Flow around the tank is strong
The CO2 level seems OK - lime green drop checker


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## Superman (12 Mar 2009)

Green surface algae shows that you have poor circulation and poor co2.
What water are you using in the drop checker? Is it 4dkh?
Use paper towels to remove it, put one down and then another half covering as you'll need to catch the film between the two.


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## Themuleous (12 Mar 2009)

It can he sod to clear.  I found having the outlet of the filter above the waters surface to it drags the green film down under water removed it after a week or so.  But it is a persistent little git.

Sam


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## Superman (12 Mar 2009)

I've increased my surface area so much that its too much, still not shifting it.


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## Midnight (12 Mar 2009)

Superman said:
			
		

> Green surface algae shows that you have poor circulation and poor co2.
> What water are you using in the drop checker? Is it 4dkh?
> Use paper towels to remove it, put one down and then another half covering as you'll need to catch the film between the two.



Yes 4dkh from AE
Circulation is good the plant sway in the flow
CO2 has been flunctuating a bit since I changed the bottle - BBA is back too


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## Superman (12 Mar 2009)

Midnight said:
			
		

> Superman said:
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Might be a daft question.. using the right reagent in the drop checker? Once I used the wrong one!


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