Keith,
You can turn off some or all but one diffuser which will add a lot more air to one unit which will clean it to some extent. Ted Lea showed me how to do that type of cleaning , but be careful to not over do it. IE make sure your pump will not damage the one diffuser that is left turned one during the cleaning. I found this worked well in my Topias when I had a diffuser in each last year. Now that the water is going down some this year, I will reset them and get them running.
