Other likely will disagree with me, but honestly, if all is good with no leaks, I would just run with the water you have in it. After 24hrs the chlorine will dissipate, and with added conditioner(s), running heavy carbon, and gfo, if you have phosphates in the water, you can clean and purify most of the impurities out of the water before you put salt in. Let it sit, and run for a week or more to make sure its good and clean. When ready to start the cycle, add salt slowly, via the sump and go from there.