There are replacement filters available which do away with the Micro-Filter. I sell a bunch of them now that our local Sundance dealer has folded. They are around $100 or so, less on line (don't forget to add shipping from some sites) but they should last anywhere from two to four years with proper care.
They look just like a regular one piece filter, but there is a divider inside which makes one part work with the small pump while the rest works with the large pump. My customers who have purchased them have been very happy with water clarity - and they save money in the long run.
Just a thought.