The most obvious cause for me in my nano all of a sudden is the light. As soon as the lights come on in the morning, the sand is clean but the diatoms start. Within hours the sand is all brown. Then the lights go off at night and by the next morning the sand is clean and it starts all over. This is a brand new occurance for me that started a couple weeks ago. I'm also getting micro bubbles attaching themselves to my macro algae. Again, these go away at night.\n\nBut why would the light all of a sudden start creating issues? This leads me to believe there is an underlying cause that is exacerbated by the light. Any ideas?\n\nThe light is an led fixture.