The ionic filters (clear pipe with resin inside and a hozelock style male fitting at each end) are not designed to be refilled. They are disposable.
They come in 12inch and 30inch variants, and (the 12 inch especially) are extremely useful to keep in the van.
I keep 2 ready at all times, with all the necessary hoses for situations where there is access to water (from a tap) but not access for hoses. Such as courtyards etc, or increasingly- no parking nearby.
You can then park-up wherever (far away) and just go to the job with a filter and pole.
For use in systems themselves (rather than on-the-fly) they trade cost for speed and convenience. They are fast and easy to replace, but they (obviously) cost more than refilling a refillable vessel.
There was a time when I wondered who would ever pay extra to save the time and hassle of refilling a vessel, but as I’ve gotten busier, I have bought a few 30-inch vessels as my time has gotten more valuable.
So, to put it simply. If you have time to spare, get a refillable vessel. If you don’t, get a disposable one.