We have a medium size paddling pool which takes around an hour to fill. I hate wasting water so the water is usually in for a few days, covered at night and topped up with fresh when it drops a bit. I noticed this morning it's a little cloudy (been up since Sat morning) - do I need chlorine of some sort? It's just for me to float about in so no risk of kids swallowing water or anything. Never occurred to me before so this may well be a really stupid question!