Cloudy water typically means the aquarium is unstable some how. Water chemistry changes are often an explanation, and if you have soft water, the pH will indeed go down between water changes unless you do something to stabilise it (typically, by either understocking the tank, by doing frequent small water changes, or by using a commercial pH buffer).
Water quality is another problem, and a "24 hour cycle" isn't a cycle at all -- by definition, a cycle means some process has gone from start to finish. What you've done is filled the tank for water and left it empty for 24 hours. Not a bad thing to do, and as good a way as any to check for leaks and to make sure the electrical accessories (like filters and heaters) are all working. But it still means the biological filter is virtually non-existent, so what you're doing is cycling the tank with a fish in it. Yes, that can cause water to go cloudy as bacteria in the water multiply rapidly ("blooming") and then die back. Can take several weeks to settle down. Algae can bloom too, and this is most common in tanks without live plants.
I must ask why you're keeping a Molly in an aquarium with soft water. Mollies quickly sicken in soft water. At the very least they need very hard freshwater, and to be truly easy fish, they do best in slightly brackish water. Adding 2-3 gram/litre marine aquarium salt mix (rather than tonic or aquarium salt) would not only fix your water hardness issue but also make your Molly very much more resistant to disease. It would, however, limit your choices of tankmates. Since Mollies do best on their own and aren't really community fish, this isn't necessarily a problem.
Cheers, Neale