Guys....
I have this problem with oily layer thingy on the surface of the water and I can never get rid of them permanently. I scoped them up but then this sticky layer will reappear in in a week time. This is very tyring for me. Any solution?
My tank was built in such a way that water that get sucked into the pump is lower than the surface of the water. (does it make sense???
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Gracias