Hey whatever works for you but it seems like a lot of unnecessary work and time to me. In the future if you add a center drain, external standpipe and a gate valve you could flush out all the crud with one pull of a handle. Better yet if it's circular tank you can inflow the water tangentially to the tank wall and create a circular flow to send the crude to the center drain which with one pull of the gate valve handle it's gone.
I have all of that and my 10% water change takes just five minutes.
