OK, perhaps you missed the point about testing more often than 3x a day if you can do it. 3x a day is the minimum, and it makes SLAM go pretty darn slow. What we're trying to convey is that if you can possibly test every hour to 2 hours, that is better and will help a lot.
Insofar as the filter, I think you may need to do a complete filter cleaning (take apart, wash it all out/off) and start all over with new DE. It sounds like your filter isn't filtering after adding the fiber clear.