Since a week or two i have problems with a white layer on top my watersurface. Because it is a planted tank, i am affraid it blocks out to many light from the lamps. I already tryed huge waterchanges, but within a day it is back. I have also put a outlet of the filter at the surface to break it, but it only helps just around the outlet. Somebody knows what it is and how i can get rid of it?