diatom filter questions

[mark]

Used to run a foam block over the bulkhead in the sump for the return pump. Removed a while back and have noticed a little more particles suspended in the display.

Reading about diatom filters for a while but mostly seeing manufacturer type posts, wondering
-don't want to clutter display, can run off a sump
-run continuously, if not how long can they sit unused (then reused without cleaning/recharging)
-running BB and siphon out display every couple/three weeks during water changes, could a diatom filter be used between changes to siphon detritus and algae and flow water back to tank (would it strip Valonia daughter cells, would the detritus plug it up)?