This is kind of weird, I think, and I hope one of y'all can tell me what's going on. About a month ago, I did a routine water change on my 55. In addition to my bucket, I use some translucent gallon jugs for changing water. As I was pouring the old water into the sink, I noticed that it looked quite blue. It looked like the same shade of blue that tank water can turn when you use certain medications, but my tank is not medicated. I filled up one of the gallon jugs with tap water and compared it to a jug full of tank water, and sure enough, the tank water was blue. I thought maybe I was overdoing it with the stress coat (my water conditioner), so I got out a syringe so I could measure exactly 1/2 ml of stress coat per gallon. It's been about a month of frequent water changes with precisely measured stress coat, and the water remains blue. When I look at the tank from the front, I can't tell, but when I view it from the side, the long way, it's definitely blue. The fish are all ok, but I'd like to know what's causing the color. Water changes don't seem to diminish it, so I'm guessing something in the tank is producing it. There are no fake decorations in there. There's only the fish, some driftwood, anubias, java moss, and two red clay flower pots. The gravel is sand-colored. Could the color maybe be caused by some kind of algae? I'm not running any carbon, but I'm planning to go buy some soon. Any ideas? Thanks!