Bill Hirsch gas tank etch

[eystein]

Have used th Bill Hirsch kit according to instructions on a very nice looking fuel tank with little dirt inside. After using the degreaser i flushed several times with clean water and dried the tank. It then appeared clean with the exeption of rust. Next, the etch seems to have removed the rust. Hovever there is now a fine layer of beige-colored silt at the bottom of the tank. Is this normal ? How do i clean it ? Do i have to repeat the processstarting again with the degreaserand then the etch over again ?