Oily looking film on the layer of water

[milindsaraswala]

My tank is nano tank details are as below

• 
  
  
  • 18 x 10 x 10 inches.
  • 2 CFL ( 13W 820lm & 30W 1980lm)
  • DIY CO2
  • HOB filter (600 L/H)
  • Ocean free aqua gro plant & shrimp soil sand (2 bags of 3 Liter)

First 2 weeks I had kept soil with very small amount of water. Than after that I planted plants then added HOB filter than after a week I added 5 Taiwan red cherry shrimp. I am not feeding them at all.
Now my issue is I have some kind of slime on the layer of water, oily. So I had change the water and I found some kind of flies very tiny all died something like 1 cm or smaller than that. I want to know, what is that and how can I remove them. Some pictures

 

[StevenF]

The film is bacteria growing on the surface of the water. I don't believe it is harmful in any way. My tank also has it. I control it by positioning my filter output so that the water from the filter has to drop one inch down to the water surface. This downward flow of water pulls the biofilm down with it. This keeps the surface clean and improves aeration.

I also have Singapore Flower shrimp in my tank. These are filter feeding shrimp they have baskets on there arms to catch any food particles in the water and they naturally move toward the filter output flow and feed off the biofilm particles in the flow.

 

[Byron]

That is a protein film. It can occur in planted tanks, and here I would agree with Steven that bacteria is part of the issue, and perhaps the soil is another factor. The "flies" are probably the tiny bugs I see in some tanks with floating plants, they hop around during the water changes. These are harmless, sometimes fish will eat them.

The only issue with a protein film is that it does impede the gas exchange that should occur at the surface. The thicker the film, the more it impedes this, and that can cause trouble--literally suffocating the tank. I rarely see this film, except in one or two tanks now and then; I invert the water changer during the water change and pull it in from just under the surface. You can usually control it by doing this, unless it is really heavy. A surface skimming addition for canister filters is an optioon, something like Steven mentioned. I tried this but found it pulled in the tiny fish, and plants clogged it up.

Byron.

 

[NickAu]

Heres an easy fix.
Raise you HOB a bit, I had a similar problem on my cube, I used a bit of Styrofoam as a spacer.

From this

To this, You can even cut a slot in the foam for the glass if you want.

This will create enough surface movement to get rid of the slick.


PS

Is that filter intake baby shrimp safe? Baby shrimp are tiny and if there is no fine mesh on the intake they will get sucked up into the filter.

 

[flchamp89]

https://www.amazon.com/gp/product/B004K9A15G/?tag=ff0d01-20

These work up to an ac70. Will last a lifetime.

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