I guess it's not really a problem, it just looks nasty. The surface of my tank is constantly covered in a nasty layer of oily stuff. I did a water change and made sure to skim a lot of that crud off about three days ago, and now it's back. I can get rid of it by taking out my overflow tube to create a waterfall into the overflow, but that's loud and annoying and then the oil just comes back the next day.
I remember reading/seeing some product that was suppose to be used to get rid of this, but I don't know if it's safe or actually works (or even what it's called...).
Anyone know what causes this? It's driving me crazy
