# Oily water ????



## sondre (Jun 1, 2011)

Hi guys,

water in my tank seems to be oily on the top. 
The only new thing i started using is calcium blocks for snails.

If it helps , here is more info :
tank is planted,i do weekly 25% water changes,i got 7 neon tetras , 1 apple snail and 20 cherry shrimp.
I done all the water tests today:
Ammonia : 0 ppm
Nitrite : 0 ppm
Nitrate : 10-20 ppm
Phostate : 0.5 ppm.

To those who think i need to do water change to get nitrates down : it doesnt help,because my tap water is 40-80 ppm in nitrates , and plants dont really help to get it down aswell .

I have never had this problem before,and since the last water change,i only added cherry shrimps and calcium block for my apple snail .


The other thing i wanted to ask : when is the time to do 100% water change and good clean up of the tank ???


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## susankat (Nov 15, 2008)

sondre said:


> Hi guys,
> 
> 
> 
> ...


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## James0816 (Jun 19, 2009)

Possible biofilm and not oil sheen? When you look at it, does multiple colors in the sheen or just like a light grayish/white film on the water?


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## jrman83 (Jul 9, 2010)

Biofilm does sort of look like oil. All of my tanks get it and seems dosing ferts adds to it since some small amount floats for a while....if its all colorful then you maybe should be concerned. Adding in thing for your snail may have made it more noticeable now.


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## sondre (Jun 1, 2011)

James0816 said:


> Possible biofilm and not oil sheen? When you look at it, does multiple colors in the sheen or just like a light grayish/white film on the water?


Its like light grayish/white film , water change didnt help , its still there .


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## James0816 (Jun 19, 2009)

sondre said:


> Its like light grayish/white film , water change didnt help , its still there .


Definately sounds like biofilm buildup. You should increase the aeration. Do you have an airstone?


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## Gizmo (Dec 6, 2010)

I've got biofilm as well (positive that's what you have). Surface agitation works to solve it, as does a protein skimmer, though you probably won't need to get the latter.


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## sondre (Jun 1, 2011)

James0816 said:


> Definately sounds like biofilm buildup. You should increase the aeration. Do you have an airstone?


yeah i got that , but only turm it on daytime,because its too noisy .


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## FAIRCHILD (Jun 30, 2011)

I have had this as well, but mostly in my tanks that aren't getting much surface agitation. After I add some air it goes away quickly. In short I agree with what has already been said. 

The folks above are far smarter than I anyway so your in great hands taking their advice.


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## James0816 (Jun 19, 2009)

The bad part is you said you run it during the day and turn it off at night. I know you said the noise is a factor, but they really should be ran just the opposite.

Another couple of options maybe....

1) lower the water level a bit. Me personally...I don't like this one but some do.
2) get a powerhead and have it directed just under the surface.


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## sondre (Jun 1, 2011)

But is it going to affect health of my fish longterm ? ( this film/oil?)

What is powerhead , lol ????


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## Gizmo (Dec 6, 2010)

The biofilm won't harm a thing.

A powerhead is basically a fully submersible water pump. Google them


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## sondre (Jun 1, 2011)

Had a look on google,does it just move water arround ?

I do have a filter , 300lph , and bubble wall,which now i keep on all day all night.

But if this biofilm is not harmfull,then i think i got nothing to worry about.

Thank you guys


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## harveya (Aug 12, 2011)

It's nothing to worry about. The effect of a power head is to increase water movement and nothing else. If you want to rid of this film the best way is to increase surface agitation or look at the food. It is a protein film nothing more nothing less.


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