It's actually on a countertop underneath a cabinet a good 15 feet from the windows. The blinds are usually kept at least partially closed.
I'm definitely not a fan of chemicals, trust me on that. I'm faced with several challenges though. One, I can't get there to take care of it, and my wife is not so knowledgable and is overworked as it is. For about 8 years now, we've had a stable tank that never needed more than routine maintenance.
Last year, however, they built a new elementary school which changed the field somewhat. We were not able to get in at all over the summer, so there was three months of a dry tank. We brought the fish home for the summer. That meant that we had to restart the tank, and due to a number of issues that meant a fairly quick start, so there wasn't much time to cycle the tank. There aren't many fish in it, but we didn't have the time to start things slow and easy. All that has created what my wife describes as the green tide of the apocalypse. Granted, I might go in and find it is only a slightly green tint to the water. She does tend to exaggerate, but for better or worse, I got her some algae fix and told her to go half dose and see if there is an improvement.
I've suggested no lights, no food, wait it out, etc. But if she's doing it, it doesn't appear to be helping.