I was experiencing a problem with diatoms so I have kept my aquarium light off until I get home from work. A ton of natural sunlight enters my apartment through the large window, so I figured the plants in the tank would be fine. The diatom situation is improving, and to my surprise, my nitrites are much much lower than before I decided to leave the light off during the day. I'm bad with colour so I could not figure out the exact level of nitrites with the test kit but it was definately over 0.8 mg/L before I kept the lights off. This was perhaps 3 or 4 days ago. I just tested minutes ago and the level is 0.1 mg/L. I'm going to test again in tomorrow to double check. I have no idea if there's any correalation or if there was an error in my testing, or whatever. Really, really curious as to what you think, know, have experienced, etc.