update: I confirmed with the owner (again) that he didn't think he used CDX. Can you test for CDX and/or Baquacil using the Taylor 2006c test kit?
------------No, but i dont see the need. you are CLOSE!-----------
I'm still trying to wrap my head around this. I just vacuumed, brushed the walls & backwashed again for good measure even though the pool looked spotless. I'm not seeing any goop in the middle of the pool, floating around, in the skimmer box or the pipes (that i can see). The filter is barely backwashing anything out after running for almost 12 hours.