I just did my first 5 gal water change on my 55 and had a big ball of grape culpera. I did the change then went to my bedroom to look a my 30, I was gone for maybe 5 min I go back to the dinning room and bam my water was all yellow and the culpera turned white. What in the heck happened? I took the rock the macro was on and tore it off and threw it away. Has anyone had this happen to them?