My first thought (8 months ago) was that it would correct itself on its own. But the brown never really went away...and then became worse. I will cut out the light and put black plastic around it. I will keep it that way for 3 days. And perhaps reduce the light cycle. In terms of nutrient load - it is low not high. And whatever I put in is aggressively consumed so much so that I cannot get chaeto to grow in the sump...but something sure was... I will report the changes...