When my tank looked like this: http://groups.msn.com/rsfish/shoebox.msnw?action=ShowPhoto&PhotoID=28 a 4 day blackout cleaned it up entirely, and adding KNO3 (which you're already doing) kept it from coming back. Rachel _______________________________________________ Aquatic-Plants mailing list Aquatic-Plants at actwin_com http://www.actwin.com/mailman/listinfo/aquatic-plants