Any Ideas?

[zoekin8yg]

Im cycling a tank at the moment, we've divided it into 4 sections siliconed in plastic bits to hold the perspex dividers. Its a 120 L tank and im running an external filter. Its not a new tank, got it off ebay, but its had a good clean etc. I keep getting a film like slime on the top of the water, I was thinking it might be some sort of slime mould, although Im not sure any ideas? Weve now re cleaned the tank and refilled it so don't know if its going to come back or not. Any ideas what it might be and or what could be causing it?

 

[Xebadir]

My first guess would be that there is little surface disruption in the tank? Hence you get a sort of slick residue on the surface. Its nothing to worry about, but depending on how your external is set up you may want to consider some sort of aeration method(airstone etc) in order to break surface tension and get additional oxygen. If you have plenty of oxygen from external filtration then its just a matter of aesthetics. Other possibilities may be what type of silicon you used(possibly leeching), and the way you have set up your dividers.

With respect to your dividers did you place a grate in them to facilitate water flow through the system? If this isnt the case then stagnation is your likely problem.

 

[zoekin8yg]

Its def not a normal slick If you see what I mean, the dividers actually arent in place at the mo, just the bits that hold them in place. The silicone was stuff from my lfs so supposedly aquarium safe. When the dividers are in place they will have holes drilled in to allow water flow

Forgot to say its very sticky and slimey not more oily like the film you normally get

 

[Xebadir]

Did you use anything on the internal of the tank to clean off silicon smudges? If so you can only try rinsing the tank.

Is the tank in direct/partial sunlight? If so it could be an algal subsisting on surface tension. Particularly if the tank has nothing in it to consume nutrient present in the water this could be the case. If so the only way to get rid of it is by adding plants to remove the excess nutrients so the algae cant propagate.

 

[zoekin8yg]

Its not in direct sunlight, I dont think it is alage, but I guess it could be its only been cycling for a short time so the nitrite and nitrate levels are still all really low. Im not sure exactly what my fiance did re the silicon, he probably did remove the smudges, The tanks been rinsed and scrubed last night so maybe that will have helped?

 

[Xebadir]

Dont worry about it too much for now, it may clear up. Particularly if its a glass bottom tank(no substrate), easiest position for bacteria to interface with O2 is surface of water. This could likely be the cause. Hope everything goes well. The scrub out could have only helped. Good Luck