Over the passed couple of weeks, my pink coraline algae, which was covering the entire back of my aquarium and all my rock, started to die, turning white. Thought maybe it was a calcium problem, so I got a test kit. The level was off the TOP of the chart, >500. OK, I'm confused. All the other levels are within limits (ph, ammonia, nitrite, nitrate, carbonate). I'm waiting for a phospate test kit to come in. Anybody got any ideas?