1) Will swimming pool water be considered as kur water?

2) Also will the water become Narjis if other non-believers also swim in it?

1) If it is a pool that has more than 384 litres, that is in all three dimensions greater than 36 hand spans, then yes

2) If it is greater than a Kurr, as long as the smell, colour or taste of the water doesn’t change it remains pure.