Having put up for ages with a trickle from the kitchen hot water tap - the cold was better from the same tap, I had the long overdue idea of checking the tap filter. On unscrewing this, it was full up with scale and bits. The hot water ran freely without it. Do I have to replace the filter (I have now cleaned it)? The tap runs perfectly well without it. The water has a softener and is not drinking water as I have a separate tap for this. What function do these meshes provide - other than restricting the flow!