in blue light it looks brown. under white light it turns out greenish. it is a dusty substance.
starting up a reeftank. done a lot to start it going. ammonia and nitrite won't drop. now i am using microbe-lift special blend in combination with micro-lift nite-out. this is what is happening. filtermaterial turns dark brown within a good day.
last ammonia check less than .25 is it going the right way?