White film on tank surface

[fort384]

What do you all make of this? I am guessing it is bacterial in nature... it is the consistency of snot floating on the top of the tank. The picture looks worse than it is. It is a very thin film. I can scoop it out with a brine shrimp net, but it grows back within a day or so.

The tank is still cycling - no bioload except for a few snails who hitch-hiked in with the plants. Plants appear healthy.

Here is some info that may help figure out the problem:
5gal tank
27W CF 6700K on for 10.5 hrs/day
ADA Aquasoil substrate
AZOO 60 mignon filter (maybe under-powered?)
Ammonia - 1.5 ppm
NitrIte - 0.25 ppm
NitrAte - 5-10 ppm (had been dosing until recently when I learned it wasn't necessary will ammonia was present)
PO4 - 1 ppm
Also dosing K
pH - 6.6
GH - ~16*
KH - ~7*
temp - 74F
CO2 - 30-40 ppm

If it is bacterial, I am thinking I could dose erythromyacin(sp?) without affecting livestock, although it could potentially set the cycle back.

Any ideas?

 

[colematthewmalaka]

i get that on one of my uncovered tanks i just scoop it off

 

[fort384]

yeah it is uncovered... my 29 never gets it and it has a glass top. Connection perhaps?

 

[colematthewmalaka]

its dust and crap in the air you should get it a cover for it it'll help

 

[fort384]

hmmm, I don't think that is what it is. I think it is something growing/alive.
I really don't want it covered. It is an ADA cube garden, no good way to even put a cover on it.

 

[colematthewmalaka]

oh ic well it could be a type of floating algae you should scoop it off

 

[fort384]

yeah, I really don't think it is algae either... it is colorless. It may be a form of cyanobacteria. But, not sure...

 

[joy13]

I get it on only one of my uncovered tanks.and I have 6 of them. The one I get it on doesn't seem to want to grow any floating plants very well, the stem and rooted plants are doing better than in the other tanks. I use the same light as I do on 3 of my other open tanks. I skim it off and the next day it is back, the fish is fine. I figure it is a bacteria bloom of some sort and don't worry about it. I tried using excel to get rid of it but it didn't help. Just a quirk of that one tank.

 

[fort384]

Joy, interesting. Thanks for the info. Has anyone else got this in their tank? I would really like to id it and eliminate it if at all possible.

 

[ezy33]

I've had this happen on both FW and SW systems, usually on new set ups. I take a paper towel and drag it across the surface to trap as much as I can into one end of the tank. Then I roll the towel up trapping as much of the film as I can. It may take two or more times but it seems to take care of the problem.