Thanks for all your help. I cleaned the gravel and cut back on the food and all seems to be going well. It has not returened since I have done this. changed about 20% of the water the other day and it looks great. just a note: I got a rena filstar xp1 filter and I cant tell you the improvment of how cler the water is. I have had this tank set up befor and never have I had such clear wter. But I must admit I did not know much about taking care of the tank...still learning but I hope to have a healthy, happy tank this time.