re: OB yard experts: how do I get rid of this?

I'm pretty sure the only way to get rid of it is by replacing the sod.....seriously. Even pulling it won't do the trick because on the underside of each individual leaf are the seeds that grow more of the shite. You need to very careful spraying anything on St. Augustine; if the product doesn't say it's for St. Augustine, then it will probably kill it. I have this stuff in my lawn too.