video of problem - http://www.youtube.com/profile?user=.../0/vkXeGR_V2LM
pics of tank - http://www.flickr.com/photos/mjnouri...57625149112625
Hi all. I'm having a problem with my 13g freshwater tank. Check it out in the video. I'm having this oil-like buildup on the top of my water. I'm not sure what it is and am hoping someone here has seen something like this before and knows what to do because I'm out of ideas! I had another tank (in the same room) and it too had the problem. I even tried RO/DI water yet all it did was prevent the buildup for another 2 days. I emptied out 95% of the water before filling it with RO/DI water too while the fish were in the other tank. I replaced the substrate, filter, water, heater and thermometer yet it still grows back with everything in the tank new (or old) in only 2 days. Mind you the tank doesn't need fish in it for the stuff to appear. I also saw it well before I put the rocks in there.
Water parameters for the tank are stable at ph=7, ammonia=0, temp=78f. (Also had the water at 72f for a few months witht he same problem) The tank currently houses 3 glofish, and 2 guppies. I can remove the oil by skimming the surface with a cup for water changes. It is also not harmful at all to the fish since they have lived with it for months.
I'm starting to think it has to be something in the room, which is in a basement. I'll setup my other tank upstairs and see how that goes as another test.
Any ideas what this stuff is or how to get rid of it?