# Algal Film



## 04kirkhamj (25 Jul 2010)

Hi all

For some time now my fish tank has had this green film forming on the surface of the water. Even after a water change it forms very quickly after (within a day). Whenever you put your finger in a gap is left in the film but this then soon closes up.

I was wondering if any of you had any ideas how to get rid of this.

I currently dose Easy Carbo, Potassium Nitrate, Potassium Phosphate and trace nutrients. I have no source of direct CO2.   

Other than this film layer, there is no major amount of algae on my plants or background. 

Thanks for any help - much appreciated


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## Jack middleton (25 Jul 2010)

I had this problem in a marine set up and increasing surface agitation resolved the problem, I don't know if it will be the same in this case but it can't hurt to try


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## PM (26 Jul 2010)

Get a skimmer attachment for your filter.


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## 04kirkhamj (26 Jul 2010)

PM said:
			
		

> Get a skimmer attachment for your filter.



That would be good however I currently do not have that much money to spend on one


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## dw1305 (26 Jul 2010)

Hi all,
You can reduce/remove the algal scum with a sheet of paper "kitchen" towel. 
If you can get hold of some floating plants that would also help - _Limnobium, Salvinia or Pistia _might be best. You look a bit under planted as well, it would be worth using _Ceratophyllum or Ceratopteris_ until  the film goes.

PM me if you can't source the plants.

cheers Darrel


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## ceg4048 (26 Jul 2010)

04kirkhamj said:
			
		

> I currently dose Easy Carbo, Potassium Nitrate, Potassium Phosphate and trace nutrients. I have no source of direct CO2.
> 
> Other than this film layer, there is no major amount of algae on my plants or background.


Hi,
   It's almost a certainty that you have too much light and not enough flow. Step number 1 is to reduce your lighting intensity. You can also increase the Easycarbo dosing. More in this thread =>http://ukaps.org/forum/viewtopic.php?f=21&t=2389

Cheers,


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## sWozzAres (27 Jul 2010)

You need a container, like a cup but bigger deeper, push it under the water just below the surface and will all fall into the container. Do it slowly, methodically and pick the right place in the tank to do it and you can get rid of it all in a few minutes.

Might be better to find out whats causing it, I had the same problem once and put it down to too much bio crud building up at the surface that eventually fed the algae. Reducing feeding or having more plants would help.


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## 04kirkhamj (27 Jul 2010)

ceg4048 said:
			
		

> 04kirkhamj said:
> 
> 
> 
> ...



Thanks for the advice so far

I have a 125l tank with a pump that does 600l an hour. So maybe an external filter would be the long term solution

However I only have standard Juwel T5 lighting with reflectors so I didn't think this was very intense lighting. I may remove the reflectors if nothing else works

For the time being I'll add more ferts and easy carbo and look at purchasing a few more plants


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## ceg4048 (28 Jul 2010)

Yes, unfortunately the problem is that we don't have an effective way to determine absolute values because there is always an interaction between:
1. the plants
2. the level of lighting
3. the CO2 level
4. the flow rate 
5. the distribution of flow
6. the nutrient levels. 
7. the water change schedule
8. the filter maintenance schedule
9. the temperature
10 the tank size
11. the aquascape layout

Weaknesses in any combination of these vital factors can cause problems, whether minor or severe. Regardless of the combination however, we do know that the net effect of these weaknesses is always malnutrition.

Because all of these are inextricably linked, it would be very easy for someone having the exact same tank, but with say, a 1500LPH filter, to conclude, yes, the lighting is adequate and is not excessive. Someone else can have the same tank/equipment and perhaps injects CO2 at a higher rate and perhaps doses nutrients at a higher level. He/she may also conclude that the lighting is adequate due to no surface film and good growth performance.

The number of combination of things that can cause malnutrition is enormous. That's why we developed a set of values for these factors which we determined through experience, were the "threshold", above which ensures a better chance of success, and below which the possibility of failure is acute.

Take item 4, flow rate for example. Our agreed threshold for continued success with this parameter is "10X the tank volume per hour" of flow rating. This means that a filter or combination of filters/powerhead(s) should have near or above a rating of 1250LPH for a 125L tank.

How about parameter 3, CO2? We agreed that 30ppm or above should be the target level, however, Excel/EasyCarbo only delivers 30% or less CO2 when dosed per bottle instructions when compared to that delivered by a pressurized gas injected cylinder.

If we interrogate that list with respect to your tank, I'm pretty sure that we can find a few more weaknesses somewhere. When the cumulative effect of these weaknesses are taken into account then the level of lighting can be considered excessive, because high light always exacerbates the weaknesses of all the other items on that list - and that is one of the few absolutes that we know is unquestionable.

Cheers,


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## sWozzAres (3 Aug 2010)

You could also try reducing feeding and/or not using flake food. My fish are medium size (4-6 inches) so they don't always eat the tiniest bits of flake food, it then stays on the surface rotting away.


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